Spec #136: Finished belongs to the Series — owner-owned poll gate, Lifecycle bucket dropped (#163)

Closes #136.

Spec #136 end to end: `finished` becomes a fact about the Series, written only by the owner, and the reader-facing Lifecycle bucket is gone.

## What landed

- **#157** — `series.finished_at bigint NOT NULL DEFAULT 0` plus the migration whose statement order is load-bearing (seed from the buckets, then flip them); both Lane queries lose the `HAVING COUNT(*) FILTER (WHERE b.status <> 'finished')` clause and gate on `finished_at = 0` instead, with the due-query/eligible-count force asymmetry kept deliberate and commented; `StatusFinished`, its API special-case 400, the web tab and the templates' Finished bucket deleted.
- **#158** — owner Finish control on the Series detail page: confirm-gated finish, instant un-finish, admin accent (never ember, nothing is destroyed), `Store.SetSeriesFinished`, the two routes behind the owner gate, and the state displayed on the list row without offering the control there.
- **#160** — reader side: derived `finished` bool on the flat Bookmark (`s.finished_at > 0`), rendered as a text-only label in both userscripts and on the web card; read-only inbound by omission from `Upsert`'s explicit `series` column list, same mechanism that already protects `cover`.
- **#161** — glossary and the stale Reader-count divergence note catch up.
- **#159** — `finished` joins the admin filter vocabulary (predicate `finished_at > 0`, label `Finished`, own aggregate count, figure last in the stats block as informational); the four clock-driven hygiene predicates (stale, never-checked, no-cover, no-chapter) exclude finished Series while unpollable, orphan and sighting-raised deliberately do not.

## Verification

`go vet ./...` and `go test ./...` green on the merged branch (Docker-backed, throwaway `postgres:17-alpine` per package). Each ticket also passed a two-axis review (spec + standards) on its own branch before merge.

Reviewed-on: #163
Co-authored-by: Sulthan Zaki <sultankiki05@gmail.com>
Co-committed-by: Sulthan Zaki <sultankiki05@gmail.com>

backend/internal/web/web.go

@@ -293,10 +293,11 @@ func libOf(q string) string {
 // buildListView loads one reader's list once and derives both the tab-filtered
 // items and the recent strip from it.
 //
-// Archived and finished series appear in their own tab and nowhere else — not
-// in All, not in Updated, not in Favourites, and not in the recent strip. An
-// archived favourite therefore shows only under Archived: Favourites means
-// "favourites I am currently reading".
+// Archived series appear in their own tab and nowhere else — not in All, not
+// in Updated, not in Favourites, and not in the recent strip. An archived
+// favourite therefore shows only under Archived: Favourites means "favourites
+// I am currently reading". There is no Finished tab: finished is a fact about
+// the Series, not a bookmark bucket (issue #157).
 func (h *Handler) buildListView(readerID int64, lib, tab string) (listView, error) {
 	all, err := h.store.List(readerID) // already ordered updated_at DESC
 	if err != nil {
@@ -327,8 +328,6 @@ func (h *Handler) buildListView(readerID int64, lib, tab string) (listView, erro
 		items = withNew
 	case "archived":
 		items = filterBookmarks(all, func(b store.Bookmark) bool { return b.Status == store.StatusArchived })
-	case "finished":
-		items = filterBookmarks(all, func(b store.Bookmark) bool { return b.Status == store.StatusFinished })
 	default:
 		tab = "all"
 		items = reading
@@ -392,7 +391,7 @@ func currentLib(r *http.Request) string {
 // writeChromeOOB appends the regions that live outside #list — the recent
 // strip, the Updated badge and the action key — as out-of-band swaps, so a
 // mutation cannot leave them describing the library as it was before the tap.
-// The key is in here because it is tab-shaped too: archived and finished swap
+// The key is in here because it is tab-shaped too: the archived bucket swaps
 // Archive for Restore.
 func (h *Handler) writeChromeOOB(w http.ResponseWriter, view listView) {
 	view.OOB = true
@@ -492,9 +491,9 @@ func (h *Handler) uiFavorite(w http.ResponseWriter, r *http.Request) {
 	h.saveAndRenderCard(w, r, b)
 }
 
-// uiStatus moves a bookmark between lifecycle buckets. This is the only place
-// a series can be marked finished — the JSON API refuses that value, so the
-// userscript cannot set it even by accident.
+// uiStatus moves a bookmark between the two lifecycle buckets. Finished is not
+// one of them: it is a fact about the Series, decided from the admin surface,
+// so the web UI's per-bookmark control cannot set it (issue #157).
 //
 // last_chapter_num is untouched, so Upsert keeps the stored updated_at and the
 // list does not reorder.
@@ -508,7 +507,7 @@ func (h *Handler) uiStatus(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	switch s := r.PostFormValue("status"); s {
-	case store.StatusReading, store.StatusArchived, store.StatusFinished:
+	case store.StatusReading, store.StatusArchived:
 		b.Status = s
 	default:
 		http.Error(w, "invalid status", http.StatusBadRequest)