Open registration to guild members (#27) (#36)

Closes #27.

Guild membership is now the whole gate. `discordCallback` checks membership
(and `DISCORD_REQUIRED_ROLE` when set), then `Store.EnsureReader` creates the
Reader on first sight and returns the same row on every later login. The
refusal returns before `EnsureReader`, so a turned-away sign-in leaves no row
behind. `OWNER_DISCORD_ID` still seeds the owner, but only as the
administrator — it no longer gates login.

The cutover grace path goes with it: `API_TOKEN`, `API_TOKEN_GRACE_UNTIL` and
the legacy branch in `httpmw.ResolveReader` are deleted, so a credential
authenticates exactly one Reader or nothing. `userscript.Handler` drops its
re-derivation too — the resolved path segment is already the credential.

New surfaces: an empty library offers both install links (behind the
tab-specific empty states, so "No favourites yet" still wins), and the owner
alone gets a Readers panel with `POST /readers/{id}/revoke`. The owner's own
row is not revocable — 404, not a self-logout.

Isolation is asserted from both directions for read, modify and delete, and
the shared-series invariant is pinned: two Readers on one series produce one
series row, two independent progresses, one poll per due cycle, and one
Reader's delete leaves the other's bookmark and the poll intact.

Verified: `go test ./...` green; live smoke against a throwaway Postgres —
empty-library state in both colour branches, roster rendering, a real revoke
through the panel (target 401s next request, owner untouched), owner
self-revoke refused 404, per-Reader `/u/<cred>` and bearer auth both 200 with
404 for an unknown credential.

Reviewed-on: #36
Co-authored-by: Sulthan Zaki <sultankiki05@gmail.com>
Co-committed-by: Sulthan Zaki <sultankiki05@gmail.com>

backend/internal/httpmw/middleware.go

@@ -3,11 +3,9 @@ package httpmw
 import (
 	"compress/gzip"
 	"context"
-	"crypto/subtle"
 	"log"
 	"net/http"
 	"strings"
-	"time"
 
 	"bookmarkmanager/backend/internal/store"
 	"bookmarkmanager/backend/internal/token"
@@ -26,39 +24,29 @@ func ReaderID(r *http.Request) int64 { return r.Context().Value(readerCtxKey).(i
 
 // ResolveReader maps a presented credential to a Reader. The credential is
 // hashed and matched against readers.token_sha256 — an equality on 32-byte
-// values, never a comparison of the credential itself — and, during the
-// cutover window, the retired global token resolves to the owner. Every
-// legacy acceptance is logged so the window can be confirmed empty before
-// the token is removed. The same resolution backs the API bearer header and
-// the userscript download path, so the window covers both.
-func ResolveReader(s *store.Store, legacy string, graceUntil time.Time, cred string) (int64, bool) {
-	if readerID, ok, err := s.ReaderIDForTokenHash(token.Hash(cred)); err != nil {
+// values, never a comparison of the credential itself. The same resolution
+// backs the API bearer header and the userscript download path, so a Reader
+// has exactly one credential with one blast radius.
+func ResolveReader(s *store.Store, cred string) (int64, bool) {
+	readerID, ok, err := s.ReaderIDForTokenHash(token.Hash(cred))
+	if err != nil {
 		log.Printf("auth: reader lookup: %v", err)
 		return 0, false
-	} else if ok {
-		return readerID, true
 	}
-
-	if legacy != "" && time.Now().Before(graceUntil) &&
-		subtle.ConstantTimeCompare([]byte(cred), []byte(legacy)) == 1 {
-		log.Printf("auth: retired global token accepted for owner reader %d (grace until %s)",
-			s.OwnerID(), graceUntil.Format(time.RFC3339))
-		return s.OwnerID(), true
-	}
-	return 0, false
+	return readerID, ok
 }
 
 // Auth guards a handler with a per-Reader bearer credential. The acting
 // Reader travels in the request context, so a handler scopes every store call
 // to exactly the Reader that authenticated.
-func Auth(s *store.Store, legacy string, graceUntil time.Time, next http.Handler) http.Handler {
+func Auth(s *store.Store, next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		h := r.Header.Get("Authorization")
 		if !strings.HasPrefix(h, bearerPrefix) {
 			http.Error(w, "unauthorized", http.StatusUnauthorized)
 			return
 		}
-		readerID, ok := ResolveReader(s, legacy, graceUntil, strings.TrimPrefix(h, bearerPrefix))
+		readerID, ok := ResolveReader(s, strings.TrimPrefix(h, bearerPrefix))
 		if !ok {
 			http.Error(w, "unauthorized", http.StatusUnauthorized)
 			return

backend/internal/store/sessions.go

@@ -2,6 +2,7 @@ package store
 
 import (
 	"database/sql"
+	"fmt"
 	"time"
 )
 
@@ -67,3 +68,13 @@ func (s *Store) DeleteSession(id string) error {
 	_, err := s.db.Exec(`DELETE FROM sessions WHERE id = $1`, id)
 	return err
 }
+
+// DeleteReaderSessions revokes every session one Reader holds — the owner's
+// remedy when a Reader's browser must be logged out everywhere at once. The
+// next request carrying any of those cookies finds no row and is rejected.
+func (s *Store) DeleteReaderSessions(readerID int64) error {
+	if _, err := s.db.Exec(`DELETE FROM sessions WHERE reader_id = $1`, readerID); err != nil {
+		return fmt.Errorf("delete sessions for reader %d: %w", readerID, err)
+	}
+	return nil
+}

backend/internal/store/store.go

@@ -169,10 +169,11 @@ const bookmarkColumns = `b.site, b.series_id, s.title, s.series_url, s.cover,
 const seriesColumns = `s.site, s.series_id, s.title, s.series_url, s.cover,
 	s.kind, s.latest_chapter, s.latest_chapter_num, s.latest_checked_at`
 
-// Owner is the person running the service: the first Reader, and the only one
-// until registration exists. The seed makes sure exactly one readers row
-// matches their Discord ID, carrying the SHA-256 of their epoch-0 userscript
-// credential (derived by internal/token, not the retired global token).
+// Owner is the person running the service: the first Reader, seeded at startup
+// so a fresh deployment has a library before anyone logs in. The seed makes
+// sure exactly one readers row matches their Discord ID, carrying the SHA-256
+// of their epoch-0 userscript credential (derived by internal/token). Every
+// other Reader is created by their own first login (EnsureReader).
 type Owner struct {
 	DiscordID string
 	// TokenHash is the SHA-256 of the epoch-0 credential; the array shape
@@ -183,15 +184,14 @@ type Owner struct {
 // Store is the Postgres-backed bookmark store.
 type Store struct {
 	db *sql.DB
-	// ownerID is the seeded owner Reader (issue #22). Authentication is still
-	// the single global token, so every request acts as this Reader; the store
-	// methods take the id explicitly so the scoping survives per-Reader auth.
+	// ownerID is the seeded owner Reader (issue #22) — the only Reader with
+	// administrative reach (revoking another Reader's sessions). Every store
+	// method takes a reader id explicitly, so ownership is never implicit.
 	ownerID int64
 }
 
-// OwnerID returns the seeded owner Reader's id — the Reader the retired
-// global token resolves to during the grace window, and the only Reader while
-// registration is closed.
+// OwnerID returns the seeded owner Reader's id: the administrator, and the
+// Reader every pre-registration bookmark belongs to.
 func (s *Store) OwnerID() int64 { return s.ownerID }
 
 // ReaderIDForTokenHash resolves the Reader whose stored credential hash
@@ -252,6 +252,66 @@ func (s *Store) RotateToken(readerID, expectedEpoch int64, newHash [32]byte) err
 	return nil
 }
 
+// EnsureReader returns the Reader registered to discordID, creating the row on
+// first sight. Registration is open to every guild member (issue #27), and the
+// Discord identity is the only thing that decides which Reader a login is: one
+// code path serves the first login and every later one, so a returning Reader
+// can never end up with a second library.
+//
+// epochZeroHash is only used for a brand-new row. An existing row keeps its
+// stored hash untouched, or a login would silently undo a rotation and revive
+// the credential the Reader rotated away from.
+func (s *Store) EnsureReader(discordID string, epochZeroHash [32]byte) (int64, error) {
+	var id int64
+	// DO UPDATE rather than DO NOTHING because only an updated row is
+	// returned by RETURNING; assigning the column to itself is the no-op that
+	// makes the existing id come back.
+	err := s.db.QueryRow(`
+		INSERT INTO readers (discord_id, token_sha256) VALUES ($1, $2)
+		ON CONFLICT (discord_id) DO UPDATE SET discord_id = readers.discord_id
+		RETURNING id`, discordID, epochZeroHash[:]).Scan(&id)
+	if err != nil {
+		return 0, fmt.Errorf("ensure reader: %w", err)
+	}
+	return id, nil
+}
+
+// ReaderSummary is one Reader as the owner's administration panel sees them:
+// who they are and how many live sessions they hold. No credential material,
+// hashed or otherwise, is exposed.
+type ReaderSummary struct {
+	ID        int64
+	DiscordID string
+	// Sessions counts unexpired session rows — what the owner revokes.
+	Sessions int
+}
+
+// Readers lists every Reader with their live session count, oldest first, so
+// the owner row (always the oldest) heads the list.
+func (s *Store) Readers() ([]ReaderSummary, error) {
+	rows, err := s.db.Query(`
+		SELECT r.id, r.discord_id,
+		       count(sess.id) FILTER (WHERE sess.expires_at > now()) AS sessions
+		FROM readers r
+		LEFT JOIN sessions sess ON sess.reader_id = r.id
+		GROUP BY r.id, r.discord_id
+		ORDER BY r.id`)
+	if err != nil {
+		return nil, fmt.Errorf("query readers: %w", err)
+	}
+	defer rows.Close()
+
+	out := []ReaderSummary{}
+	for rows.Next() {
+		var r ReaderSummary
+		if err := rows.Scan(&r.ID, &r.DiscordID, &r.Sessions); err != nil {
+			return nil, fmt.Errorf("scan reader: %w", err)
+		}
+		out = append(out, r)
+	}
+	return out, rows.Err()
+}
+
 // readersMigration is the version that creates the readers table. The owner
 // seed runs between two migrate passes, so that the run-once migration which
 // attaches existing bookmarks (0004) finds the owner row.

backend/internal/store/store_test.go

@@ -16,7 +16,7 @@ import (
 func TestMain(m *testing.M) { os.Exit(pgtest.Main(m)) }
 
 // testOwner is the owner every test store seeds. Tests that need a second
-// reader insert one directly (see secondReader).
+// reader register one (see secondReader).
 var testOwner = Owner{DiscordID: "test-owner", TokenHash: sha256.Sum256([]byte("owner-token-hash"))}
 
 func newTestStore(t *testing.T) *Store {
@@ -29,17 +29,14 @@ func newTestStore(t *testing.T) *Store {
 	return store
 }
 
-// secondReader inserts an extra reader row and returns its id. The store API
-// has no reader-creation path yet — the seed is the only one — so tests that
-// need reader isolation insert directly.
+// secondReader registers an extra reader through the same path a first login
+// takes, and returns its id.
 func secondReader(t *testing.T, s *Store) int64 {
 	t.Helper()
-	hash := sha256.Sum256([]byte("second-token-hash"))
-	var id int64
-	if err := s.db.QueryRow(
-		`INSERT INTO readers (discord_id, token_sha256) VALUES ($1, $2) RETURNING id`,
-		"second-"+strconv.FormatInt(time.Now().UnixNano(), 10), hash[:]).Scan(&id); err != nil {
-		t.Fatalf("seed second reader: %v", err)
+	discordID := "second-" + strconv.FormatInt(time.Now().UnixNano(), 10)
+	id, err := s.EnsureReader(discordID, sha256.Sum256([]byte("token-"+discordID)))
+	if err != nil {
+		t.Fatalf("register second reader: %v", err)
 	}
 	return id
 }
@@ -1052,3 +1049,153 @@ func TestDeleteReaderCascadesToBookmarks(t *testing.T) {
 		t.Fatalf("series = %+v, want it kept after its only reader was deleted", sr)
 	}
 }
+
+// Registration is one code path: the first sight of a Discord identity creates
+// the Reader, every later one returns the same row. The epoch-0 hash argument
+// is for creation only — a returning Reader who has rotated must not have that
+// rotation undone by logging in again.
+func TestEnsureReaderCreatesOnceAndNeverClobbersARotation(t *testing.T) {
+	s := newTestStore(t)
+	first, err := s.EnsureReader("new-member", sha256.Sum256([]byte("cred-epoch-0")))
+	if err != nil {
+		t.Fatalf("EnsureReader: %v", err)
+	}
+	if first == s.OwnerID() {
+		t.Fatal("a new Discord identity resolved to the owner Reader")
+	}
+	if id, ok, err := s.ReaderIDForTokenHash(sha256.Sum256([]byte("cred-epoch-0"))); err != nil || !ok || id != first {
+		t.Fatalf("new Reader's credential resolved to (%d, %v, %v), want (%d, true, nil)", id, ok, err, first)
+	}
+
+	rotated := sha256.Sum256([]byte("cred-epoch-1"))
+	if err := s.RotateToken(first, 0, rotated); err != nil {
+		t.Fatalf("RotateToken: %v", err)
+	}
+
+	again, err := s.EnsureReader("new-member", sha256.Sum256([]byte("cred-epoch-0")))
+	if err != nil {
+		t.Fatalf("second EnsureReader: %v", err)
+	}
+	if again != first {
+		t.Fatalf("second login returned Reader %d, want the existing %d", again, first)
+	}
+	if _, ok, err := s.ReaderIDForTokenHash(sha256.Sum256([]byte("cred-epoch-0"))); err != nil {
+		t.Fatalf("stale lookup: %v", err)
+	} else if ok {
+		t.Fatal("logging in again revived the pre-rotation credential")
+	}
+	if id, ok, err := s.ReaderIDForTokenHash(rotated); err != nil || !ok || id != first {
+		t.Fatalf("rotated credential resolved to (%d, %v, %v), want the same Reader", id, ok, err)
+	}
+
+	// Signing in as the owner's own Discord identity reuses the seeded row
+	// rather than minting a duplicate library.
+	if id, err := s.EnsureReader(testOwner.DiscordID, sha256.Sum256([]byte("ignored"))); err != nil {
+		t.Fatalf("EnsureReader(owner): %v", err)
+	} else if id != s.OwnerID() {
+		t.Fatalf("owner login returned Reader %d, want the seeded owner %d", id, s.OwnerID())
+	}
+}
+
+// The owner's administration view: who exists and how many live sessions each
+// holds. Revocation drops all of one Reader's sessions and nobody else's.
+func TestReadersAndSessionRevocation(t *testing.T) {
+	s := newTestStore(t)
+	other := secondReader(t, s)
+	for _, id := range []string{"own-1", "own-2"} {
+		if _, err := s.CreateSession(id, s.OwnerID(), time.Hour); err != nil {
+			t.Fatalf("CreateSession(%s): %v", id, err)
+		}
+	}
+	if _, err := s.CreateSession("other-1", other, time.Hour); err != nil {
+		t.Fatalf("CreateSession(other): %v", err)
+	}
+	// An expired row must not be counted as a session the owner can revoke.
+	if _, err := s.CreateSession("other-dead", other, -time.Minute); err != nil {
+		t.Fatalf("CreateSession(expired): %v", err)
+	}
+
+	readers, err := s.Readers()
+	if err != nil {
+		t.Fatalf("Readers: %v", err)
+	}
+	if len(readers) != 2 || readers[0].ID != s.OwnerID() || readers[1].ID != other {
+		t.Fatalf("readers = %+v, want the owner then the second Reader", readers)
+	}
+	if readers[0].DiscordID != testOwner.DiscordID {
+		t.Fatalf("owner discord id = %q, want %q", readers[0].DiscordID, testOwner.DiscordID)
+	}
+	if readers[0].Sessions != 2 || readers[1].Sessions != 1 {
+		t.Fatalf("session counts = %d, %d; want 2 and 1 live", readers[0].Sessions, readers[1].Sessions)
+	}
+
+	if err := s.DeleteReaderSessions(other); err != nil {
+		t.Fatalf("DeleteReaderSessions: %v", err)
+	}
+	if _, ok, err := s.GetSession("other-1", time.Now()); err != nil || ok {
+		t.Fatalf("revoked session still resolves: ok=%v err=%v", ok, err)
+	}
+	if _, ok, err := s.GetSession("own-1", time.Now()); err != nil || !ok {
+		t.Fatalf("owner's session was collateral: ok=%v err=%v", ok, err)
+	}
+}
+
+// Two Readers on one Series: one series row, two independent progresses. The
+// second Reader starts at zero however far the first has read, and the shared
+// row is still due exactly once.
+func TestTwoReadersShareOneSeriesWithIndependentProgress(t *testing.T) {
+	s := newTestStore(t)
+	other := secondReader(t, s)
+	if _, err := s.Upsert(s.OwnerID(), Bookmark{
+		Key: "asura:solo", Site: "asura", SeriesID: "solo",
+		Title: "Solo Leveling", SeriesURL: "https://asurascans.com/comics/solo",
+		LastChapter: "Chapter 200", LastChapterNum: 200, UpdatedAt: 1000,
+	}); err != nil {
+		t.Fatalf("seed owner: %v", err)
+	}
+	theirs, err := s.Upsert(other, Bookmark{
+		Key: "asura:solo", Site: "asura", SeriesID: "solo", UpdatedAt: 2000,
+	})
+	if err != nil {
+		t.Fatalf("seed other: %v", err)
+	}
+	if theirs.LastChapterNum != 0 || theirs.LastChapter != "" {
+		t.Fatalf("second Reader's progress = %+v, want zero regardless of the first's 200", theirs)
+	}
+	// The shared facts are still shared: the series row it joined to is the
+	// one the first Reader created.
+	if theirs.Title != "Solo Leveling" {
+		t.Fatalf("second Reader's title = %q, want the shared series title", theirs.Title)
+	}
+	var series int
+	if err := s.db.QueryRow(`SELECT count(*) FROM series`).Scan(&series); err != nil {
+		t.Fatalf("count series: %v", err)
+	}
+	if series != 1 {
+		t.Fatalf("series rows = %d, want 1 shared row for two bookmarks", series)
+	}
+
+	due, err := s.DueForLatestCheck(time.Now().UnixMilli(), 10)
+	if err != nil {
+		t.Fatalf("DueForLatestCheck: %v", err)
+	}
+	if len(due) != 1 || due[0].Key() != "asura:solo" {
+		t.Fatalf("due = %+v, want the shared series exactly once per cycle", due)
+	}
+
+	// One Reader dropping their bookmark leaves the other's intact and the
+	// series still polled.
+	if err := s.Delete(other, "asura:solo"); err != nil {
+		t.Fatalf("Delete(other): %v", err)
+	}
+	if b, ok, err := s.Get(s.OwnerID(), "asura:solo"); err != nil || !ok || b.LastChapterNum != 200 {
+		t.Fatalf("owner's bookmark after the other's delete = %+v ok=%v err=%v, want it intact", b, ok, err)
+	}
+	due, err = s.DueForLatestCheck(time.Now().UnixMilli(), 10)
+	if err != nil {
+		t.Fatalf("DueForLatestCheck after delete: %v", err)
+	}
+	if len(due) != 1 || due[0].Key() != "asura:solo" {
+		t.Fatalf("due after one Reader left = %+v, want the series still polled", due)
+	}
+}

backend/internal/userscript/userscript.go

@@ -10,7 +10,6 @@ import (
 
 	"bookmarkmanager/backend/internal/httpmw"
 	"bookmarkmanager/backend/internal/store"
-	"bookmarkmanager/backend/internal/token"
 )
 
 // tokenPlaceholder is what the bindmounted userscript carries where the
@@ -87,26 +86,15 @@ func Render(w http.ResponseWriter, r *http.Request, path, credential string) {
 // the route exists. The same credential authenticates the API bearer header,
 // so the two are one secret with one blast radius.
 //
-// The credential substituted is the resolved Reader's derived one, not the
-// raw path segment: while the retired global token is still accepted during
-// the grace window (httpmw.ResolveReader), an already-installed script
-// polling its legacy URL is served a copy carrying the Reader's own
-// credential, so the next update poll migrates the device onto its per-Reader
-// path — the window empties itself instead of ending in a silent 401 for
-// every device that never visited the web UI.
-func Handler(s *store.Store, tokenKey []byte, legacy string, graceUntil time.Time, path string) http.HandlerFunc {
+// The path segment is the credential itself, so once it resolves it is also
+// exactly what the served copy must carry — no re-derivation needed.
+func Handler(s *store.Store, path string) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		readerID, ok := httpmw.ResolveReader(s, legacy, graceUntil, r.PathValue("token"))
-		if !ok {
+		cred := r.PathValue("token")
+		if _, ok := httpmw.ResolveReader(s, cred); !ok {
 			http.NotFound(w, r)
 			return
 		}
-		discordID, epoch, err := s.ReaderTokenInfo(readerID)
-		if err != nil {
-			log.Printf("userscript: reader %d token info: %v", readerID, err)
-			http.NotFound(w, r)
-			return
-		}
-		Render(w, r, path, token.Token(tokenKey, discordID, epoch))
+		Render(w, r, path, cred)
 	}
 }

backend/internal/web/discord.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"bookmarkmanager/backend/internal/session"
+	"bookmarkmanager/backend/internal/token"
 )
 
 const (
@@ -50,9 +51,6 @@ type DiscordConfig struct {
 	// RedirectURI is the full public URL of the callback — Discord requires
 	// the exact string, so it is configured, never derived from headers.
 	RedirectURI string
-	// OwnerDiscordID is the only Discord identity allowed to sign in until
-	// registration exists (issue #23).
-	OwnerDiscordID string
 }
 
 // oauthStates stores one-time sign-in states. A state is generated at
@@ -166,14 +164,6 @@ func (h *Handler) discordCallback(w http.ResponseWriter, r *http.Request) {
 			"Discord sign-in is unavailable right now. Try again in a moment.")
 		return
 	}
-
-	if userID != h.discord.OwnerDiscordID {
-		h.limiter.Fail(ip, time.Now())
-		h.renderLogin(w, http.StatusForbidden,
-			"This Discord account is not the library owner.")
-		return
-	}
-
 	member, isMember, err := h.discordMember(r.Context(), tok.AccessToken)
 	if err != nil {
 		h.limiter.Fail(ip, time.Now())
@@ -185,6 +175,10 @@ func (h *Handler) discordCallback(w http.ResponseWriter, r *http.Request) {
 	// The refusal is the same for a non-member and a member without the
 	// required role, and it names neither the guild nor its id: an outsider
 	// cannot tell whether the guild exists, let alone which one gates.
+	//
+	// It also returns before EnsureReader, so a refused sign-in leaves no
+	// Reader row behind — the gate is the only thing standing between guild
+	// membership and a library.
 	if !isMember || (h.discord.RequiredRole != "" && !slices.Contains(member.Roles, h.discord.RequiredRole)) {
 		h.limiter.Fail(ip, time.Now())
 		h.renderLogin(w, http.StatusForbidden,
@@ -192,8 +186,19 @@ func (h *Handler) discordCallback(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Registration is the login (issue #27): first sight of a guild member
+	// creates their Reader, every later sight returns the same one. Their
+	// userscript credential is derived at epoch 0 the way the owner's is, so
+	// the install links work before they have read anything.
+	readerID, err := h.store.EnsureReader(userID, token.Hash(token.Token(h.tokenKey, userID, 0)))
+	if err != nil {
+		log.Printf("register reader: %v", err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+
 	h.limiter.Reset(ip)
-	sess, err := h.store.CreateSession(session.NewID(), h.readerID, session.SessionTTL)
+	sess, err := h.store.CreateSession(session.NewID(), readerID, session.SessionTTL)
 	if err != nil {
 		log.Printf("create session: %v", err)
 		http.Error(w, "internal error", http.StatusInternalServerError)

backend/internal/web/static/style.css

@@ -290,6 +290,33 @@ button { cursor: pointer; }
   letter-spacing: .04em;
 }
 
+/* ---- reader roster (owner only): same hairline panel, one row per Reader ---- */
+.readerlist { margin: 0; padding: 0; list-style: none; }
+.readerlist li {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: 4px 16px;
+  min-height: 44px;
+  border-top: 1px solid var(--rule);
+}
+.readerlist form { margin: 0 0 0 auto; }
+.reader-id {
+  font: 500 13px/1.4 var(--font-mono);
+  letter-spacing: .04em;
+  color: var(--paper);
+}
+.reader-sessions {
+  font: 500 10px/1 var(--font-mono);
+  letter-spacing: .14em;
+  text-transform: uppercase;
+  color: var(--mute);
+}
+/* Revocation cuts someone off, so it wears --danger. Ember stays reserved for
+   the new-chapter signal. */
+.ghost.danger { color: var(--danger); }
+.ghost.danger:hover { color: var(--danger); border-bottom-color: var(--danger); }
+
 .chrome { display: flex; flex-direction: column; }
 
 .searchbar {

backend/internal/web/templates/app.html

@@ -76,6 +76,8 @@
 
   {{template "setup" .}}
 
+  {{if .Owner}}{{template "readers" .}}{{end}}
+
   {{template "keyrow" .}}
 
   {{template "recent" .}}

backend/internal/web/templates/list.html

@@ -16,6 +16,17 @@
   <div class="empty"><strong>Nothing archived.</strong><p>Shelve a series to park it here — it keeps getting checked for new chapters.</p></div>
 {{else if eq .Tab "finished"}}
   <div class="empty"><strong>Nothing finished yet.</strong><p>Mark a series finished and it moves out of your reading list.</p></div>
+{{else if .EmptyLibrary}}
+  {{/* Nothing in either library, so the links are the only thing this page can
+       usefully say. Both scripts: the two libraries are separate installs. */}}
+  <div class="empty">
+    <strong>Nothing here yet.</strong>
+    <p>Install the userscripts, then open a series and read a chapter — bookmarks arrive on their own.</p>
+    <p class="setup-links">
+      <a class="ghost" href="/install/manga-bookmark.user.js">Install Manga script</a>
+      <a class="ghost" href="/install/novel-bookmark.user.js">Install Novels script</a>
+    </p>
+  </div>
 {{else}}
   <div class="empty"><strong>Nothing here yet.</strong><p>Bookmarks appear once the userscript records a chapter.</p></div>
 {{end}}

backend/internal/web/templates/readers.html

@@ -0,0 +1,29 @@
+{{/* The owner's Reader roster. Rendered only for the owner (listView.Owner),
+     and re-rendered whole as the response to a revocation so the session
+     counts cannot describe the state before the tap. Revocation is
+     confirm-gated: it signs someone out of every device at once. */}}
+{{define "readers"}}
+<details class="setup" id="readers">
+  <summary>Readers</summary>
+  <p class="setup-copy">Everyone who has signed in through Discord. Revoking
+    signs a Reader out of every device; their library and bookmarks are
+    untouched, and they can sign in again.</p>
+  <ul class="readerlist">
+    {{range .Readers}}
+    <li>
+      <span class="reader-id">{{.DiscordID}}</span>
+      <span class="reader-sessions">{{.Sessions}} session{{if ne .Sessions 1}}s{{end}}</span>
+      {{/* The owner's own row never offers Revoke: it is the one row where the
+           button would sign the tapping browser out, and the endpoint refuses
+           it anyway. Logout is the deliberate way to do that. */}}
+      {{if and .Sessions (ne .ID $.OwnerID)}}
+      <form hx-post="/readers/{{.ID}}/revoke" hx-target="#readers" hx-swap="outerHTML"
+            hx-confirm="Revoking signs this Reader out on every device immediately. Revoke?">
+        <button type="submit" class="ghost danger">Revoke sessions</button>
+      </form>
+      {{end}}
+    </li>
+    {{end}}
+  </ul>
+</details>
+{{end}}

backend/internal/web/web.go

@@ -34,10 +34,6 @@ const RecentCount = 5
 // representations (HTML versus JSON) to different clients under different auth.
 type Handler struct {
 	store *store.Store
-	// readerID is the owner Reader's id, the only Reader that can exist
-	// while registration is closed (issue #23). Every session row points at
-	// it, so it is also the Reader the UI acts as.
-	readerID int64
 	// tokenKey derives Readers' userscript credentials (internal/token): the
 	// install endpoints render the scripts with the credential inside, which
 	// is the one place the UI needs the secret.
@@ -76,6 +72,19 @@ type listView struct {
 	// Rotated marks the setup panel as having just rotated the credential:
 	// it swaps the reinstall warning in over the button row.
 	Rotated bool
+	// EmptyLibrary means this Reader holds no bookmarks in either library, so
+	// the empty state can offer the installs instead of reporting on a filter.
+	// It is not "newly registered": a Reader who deletes their last bookmark is
+	// in the same position and needs the same links.
+	EmptyLibrary bool
+	// Owner marks the acting Reader as the deployment's owner, which unlocks
+	// the Readers panel. Nothing else in the UI differs.
+	Owner bool
+	// Readers is the owner's roster, populated only for the owner's own page
+	// render and the revocation fragment. OwnerID travels with it so the roster
+	// can tell the owner's own row apart from the Readers they may revoke.
+	Readers []store.ReaderSummary
+	OwnerID int64
 }
 
 // PageURL and ListURL are the two link shapes every tab needs. Building them
@@ -102,14 +111,13 @@ type loginView struct {
 
 // New parses every template up front so a broken one kills the process at
 // startup rather than the first request that touches it.
-func New(s *store.Store, readerID int64, discord DiscordConfig, tokenKey []byte, mangaPath, novelPath string) (*Handler, error) {
+func New(s *store.Store, discord DiscordConfig, tokenKey []byte, mangaPath, novelPath string) (*Handler, error) {
 	tmpl, err := template.ParseFS(templateFS, "templates/*.html")
 	if err != nil {
 		return nil, err
 	}
 	return &Handler{
 		store:               s,
-		readerID:            readerID,
 		tokenKey:            tokenKey,
 		mangaUserscriptPath: mangaPath,
 		novelUserscriptPath: novelPath,
@@ -141,6 +149,9 @@ func (h *Handler) Register(mux *http.ServeMux) {
 	mux.HandleFunc("GET /install/manga-bookmark.user.js", h.requireSession(h.installUserscript("manga-bookmark.user.js")))
 	mux.HandleFunc("GET /install/novel-bookmark.user.js", h.requireSession(h.installUserscript("novel-bookmark.user.js")))
 	mux.HandleFunc("POST /rotate-token", h.requireSession(h.rotateToken))
+
+	// Owner-only: the one place the UI crosses the Reader boundary.
+	mux.HandleFunc("POST /readers/{id}/revoke", h.requireSession(h.revokeReaderSessions))
 }
 
 // staticHandler serves the embedded assets. An hour, not longer: assets are
@@ -229,6 +240,14 @@ func (h *Handler) index(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "internal error", http.StatusInternalServerError)
 		return
 	}
+	if readerID == h.store.OwnerID() {
+		view.Owner, view.OwnerID = true, readerID
+		if view.Readers, err = h.store.Readers(); err != nil {
+			log.Printf("index readers: %v", err)
+			http.Error(w, "internal error", http.StatusInternalServerError)
+			return
+		}
+	}
 	h.render(w, http.StatusOK, "app", view)
 }
 
@@ -276,6 +295,10 @@ func (h *Handler) buildListView(readerID int64, lib, tab string) (listView, erro
 	if err != nil {
 		return listView{}, err
 	}
+	// Taken before the filter narrows the slice: a Reader with novels but no
+	// manga has a working install already, and does not need to be told to go
+	// and get one.
+	emptyLibrary := len(all) == 0
 	// Narrow to one library first: reading, withNew and recent all derive from
 	// this slice, so doing it later would let the other library's rows into the
 	// strip and the Updated badge.
@@ -319,7 +342,8 @@ func (h *Handler) buildListView(readerID int64, lib, tab string) (listView, erro
 			recent = recent[:RecentCount]
 		}
 	}
-	return listView{Lib: lib, Tab: tab, Recent: recent, Items: items, NewCount: len(withNew)}, nil
+	return listView{Lib: lib, Tab: tab, Recent: recent, Items: items,
+		NewCount: len(withNew), EmptyLibrary: emptyLibrary}, nil
 }
 
 func (h *Handler) uiList(w http.ResponseWriter, r *http.Request) {
@@ -594,3 +618,40 @@ func (h *Handler) rotateToken(w http.ResponseWriter, r *http.Request) {
 	view := listView{Lib: store.KindManga, Rotated: true}
 	h.render(w, http.StatusOK, "setup", view)
 }
+
+// revokeReaderSessions logs one Reader out of every browser they are signed
+// in on. Owner-only: it reaches across the Reader boundary every other handler
+// respects, so the guard is a comparison against the seeded owner rather than
+// a role a Reader could acquire. A non-owner gets 404 — the panel does not
+// exist for them, so neither should the endpoint.
+func (h *Handler) revokeReaderSessions(w http.ResponseWriter, r *http.Request) {
+	if readerOf(r) != h.store.OwnerID() {
+		http.NotFound(w, r)
+		return
+	}
+	target, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
+	if err != nil {
+		http.Error(w, "bad reader id", http.StatusBadRequest)
+		return
+	}
+	// The owner is not one of the Readers this endpoint reaches: revoking
+	// themselves would sign out the browser making the request, which is what
+	// logout is for. The roster hides the button; this refuses the hand-rolled
+	// POST behind it.
+	if target == h.store.OwnerID() {
+		http.NotFound(w, r)
+		return
+	}
+	if err := h.store.DeleteReaderSessions(target); err != nil {
+		log.Printf("revoke sessions: %v", err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	readers, err := h.store.Readers()
+	if err != nil {
+		log.Printf("revoke sessions: %v", err)
+		http.Error(w, "internal error", http.StatusInternalServerError)
+		return
+	}
+	h.render(w, http.StatusOK, "readers", listView{Owner: true, Readers: readers, OwnerID: h.store.OwnerID()})
+}