Admin dashboard: pages, Lane observability, poll pass log, per-Series intervention (#134) (#148)

Spec #134, all ten tickets. Closes #134.

## What ships

The admin surface becomes four bookmarkable addresses behind one nav row, and Lane observability stops dying with the process.

- **#138** `/admin` splits into Overview, Lanes, Readers, Series, each a real route with the active tab underlined.
- **#139** `poll_passes` and `poll_lanes` land as durable tables with their store surface.
- **#140** cross-Series admin read model, with the privacy boundary in the projection: the Reader id that raised a Latest Chapter never leaves the store package.
- **#141** the poller records exactly one pass row per exit, with a skip reason and outcome counts.
- **#142** Series list: eight hygiene filters, Site and Library narrowing, paging — all of it in the query string, so a filtered list is a bookmark.
- **#143** Overview: a three-state verdict line and a stats block where every non-zero figure links to the list that counts it.
- **#144** per-Series detail page, keyed by the `site:series_id` composite the rest of the system already uses.
- **#145** the Lanes page reads the database; the in-memory Lane state, `web.LaneReporter` and `latest.Status` are deleted.
- **#146** Forced Poll: *Check now* stamps `series.force_poll_at` and never commands the poller.
- **#147** pause and resume one Site's Lane, with a mandatory 1h/6h/24h expiry.

## Shape of the design

Two decisions carry the rest. **Commands go through the database, never at the poller**: both *Check now* and a Lane pause write a row the next pass reads, so they survive a restart and the whole surface stays testable with no poller running. And **pending is derived, never stored** — the request stamp being newer than the check stamp — which self-clears on the check stamp with no second write and no sweeper, because the check stamp is written before the fetch.

ADRs: `docs/adr/0012-persisted-lane-state.md`, `docs/adr/0013-commands-through-the-database.md`.

## Verification

`go test ./...` green on the merged base (`264839e`), all packages, Docker-backed. `gofmt -l` and `go vet` clean.

Every ticket was reviewed on both axes (`cr-spec` + `cr-standards`) before merge.

## Known, non-blocking

- **#143** the verdict ignores never-reported Lanes when other Lanes have reported, and the per-Site table lists Sites that have Series rather than the whole registry. The ticket prose asks for eight hygiene figures per Site; the design mock and the landed `.tbl.sites` grid both say six columns, and the mock won.
- **#146** two `SeriesPage` scans per press instead of a keyed read — `ponytail:`-commented in-tree with the upgrade path.
- **#147** a paused Site with no pass row yet renders no row and so no control, since the Lanes page lists Sites that have passed.
- **#141** a sibling browser Lane declining at the top of a pass records as `sidecar-down`. Specified deliberately; the later spec in this series settles it.

Reviewed-on: #148
Co-authored-by: Sulthan Zaki <sultankiki05@gmail.com>
Co-committed-by: Sulthan Zaki <sultankiki05@gmail.com>

backend/main.go

@@ -54,6 +54,11 @@ type Config struct {
 	// /u/{token}/novel-bookmark.user.js. Same bindmount, second script: the
 	// two libraries are separate installs.
 	NovelUserscriptPath string
+	// BrowserWSURL is the CDP websocket the poller's browser Sites read
+	// through. Set means a browser sidecar is configured in this deployment —
+	// the Lanes page reports the fact and derives reachability from the pass
+	// log rather than asking the poller (issue #145).
+	BrowserWSURL string
 	// LatestPoll configures the background latest-chapter fetcher.
 	LatestPoll LatestPoll
 }
@@ -108,6 +113,7 @@ func loadConfig() Config {
 		OwnerDiscordID:      os.Getenv("OWNER_DISCORD_ID"),
 		UserscriptPath:      envOr("USERSCRIPT_PATH", "/userscript/manga-bookmark.user.js"),
 		NovelUserscriptPath: envOr("NOVEL_USERSCRIPT_PATH", "/userscript/novel-bookmark.user.js"),
+		BrowserWSURL:        os.Getenv("BROWSER_WS_URL"),
 		LatestPoll:          loadLatestPoll(),
 	}
 	c.Discord = web.DiscordConfig{
@@ -130,9 +136,10 @@ func loadConfig() Config {
 // preflight OPTIONS short-circuits before auth; /bookmarks* is auth-protected,
 // /healthz is public.
 //
-// lanes may be nil — polling disabled, or its client could not be built. The
-// admin page reports that rather than pretending Lanes exist.
-func newRouter(s *store.Store, cfg Config, lanes web.LaneReporter) http.Handler {
+// The web layer learns the deployment's poller and browser config from cfg —
+// nothing of the running poller is wired through here; the Lanes page reads
+// the database (issue #145).
+func newRouter(s *store.Store, cfg Config) http.Handler {
 	mux := http.NewServeMux()
 	h := &api.Handler{Store: s}
 	mux.HandleFunc("GET /healthz", api.Healthz)
@@ -161,9 +168,12 @@ func newRouter(s *store.Store, cfg Config, lanes web.LaneReporter) http.Handler
 	mux.Handle("/bookmarks/", auth)
 
 	// The browser UI is always registered; signing in is Discord OAuth, so
-	// there is no password to forget and no gate to leave unset.
+	// there is no password to forget and no gate to leave unset. The poller
+	// and browser facts are config, not the poller's: the Lanes page reads
+	// the pass log and reports the deployment as configured.
 	wh, err := web.New(s, cfg.Discord, []byte(cfg.TokenKey),
-		cfg.UserscriptPath, cfg.NovelUserscriptPath, lanes)
+		cfg.UserscriptPath, cfg.NovelUserscriptPath,
+		cfg.LatestPoll.Enabled, strings.TrimSpace(cfg.BrowserWSURL) != "")
 	if err != nil {
 		log.Fatalf("web handler: %v", err)
 	}
@@ -241,7 +251,7 @@ func main() {
 	var browser latest.Fetcher
 	pollCtx, stopPoll := context.WithCancel(context.Background())
 	defer stopPoll()
-	if ws := strings.TrimSpace(os.Getenv("BROWSER_WS_URL")); ws != "" {
+	if ws := strings.TrimSpace(cfg.BrowserWSURL); ws != "" {
 		bf, err := latest.NewBrowserFetcher(ws)
 		if err != nil {
 			log.Printf("browser fetcher disabled: %v", err)
@@ -278,17 +288,14 @@ func main() {
 		}
 		s.OnSeriesCreated = acq.Acquire
 	}
-	// A nil *Poller must not become a non-nil interface holding a nil pointer:
-	// the admin page tests the reporter for nil to decide whether anything is
-	// polling at all.
-	var lanes web.LaneReporter
-	if poller := startLatestPoller(pollCtx, s, cfg.LatestPoll, browser); poller != nil {
-		lanes = poller
-	}
+	// The poller's only connection to the web layer is the database now: it is
+	// started for its own sake, and the Lanes page reads the pass rows it
+	// records (issue #145).
+	startLatestPoller(pollCtx, s, cfg.LatestPoll, browser)
 
 	srv := &http.Server{
 		Addr:              ":" + cfg.Port,
-		Handler:           newRouter(s, cfg, lanes),
+		Handler:           newRouter(s, cfg),
 		ReadHeaderTimeout: 10 * time.Second,
 	}
 
@@ -336,7 +343,8 @@ func newLatestPoller(s *store.Store, cfg LatestPoll, fetch, browser latest.Fetch
 // HTTP client cannot be built. Any problem here is logged and skipped: this
 // feature going missing degrades the service to userscript-only latest-chapter
 // tracking, which is exactly how it behaved before. It returns the running
-// Poller, or nil when there is none — the admin page's Lane status reads it.
+// Poller, or nil when there is none; the caller starts it for its own sake —
+// the Lanes page reads the pass log, so no return value is wired anywhere.
 func startLatestPoller(ctx context.Context, s *store.Store, cfg LatestPoll, browser latest.Fetcher) *latest.Poller {
 	if !cfg.Enabled {
 		log.Println("latest-chapter poller: disabled by config")