Guidance for OpenCode (and Claude Code) working under `userscript/`. See root `AGENTS.md` for the project-wide architecture diagram, hard constraints, and design system.

### Userscript structure (single IIFE, `manga-bookmark.user.js`)

1. **Site adapters** — one per host, `detect(location, document)` return page `type` + IDs. Identify type/IDs from **URL regex** (most stable); pull `title` from **`og:title`** (or the page heading where a site ships no og: tags), not CSS classes. **No adapter reads a cover**: the backend acquires, stores and serves every Cover from its own origin (ADR-0007), the wire's `cover` is already an address on our origin, and `apiPut` strips any `cover` off an outgoing body.
2. **API client** — `apiGet/apiPut/apiDelete` with bearer header; `localStorage` key `bmgr:manga:cache` for instant render + offline fallback.
3. **Progress logic** — auto-upsert `last_chapter` only when `chapterNum >= stored last_chapter_num` (re-reading old chapters must not regress progress; unparseable -> set current). Manual panel override forces any value.
4. **Retry queue** — every write go through `pushBookmark`/`pushDelete`, so
   failed mutation park in `localStorage` (`bmgr:manga:queue`) and replayed on
   next navigation, reconnect, or `refresh()`. Entries are markers
   (`{key, op, sendStatus, attempts}`), never payloads — body read from
   cache at send time, so one entry per key give ordering and coalescing for
   free. `sendStatus` is **sticky**: while archive pending, later writes to
   that key keep carrying bucket, which stop successful
   in-between write from silently un-archiving series. `refresh()` drains
   before it fetches and overlays anything still pending, so list never
   flaps. 400 drops entry, 401 abort pass and keep queue, and
   transient failures retry to cap of 10. Latest-chapter writes deliberately
   stay out of queue. See
   `docs/superpowers/specs/2026-07-27-offline-retry-queue-design.md`.
5. **UI** — rendered inside **Shadow DOM** root to isolate from site CSS
   (critical on mobile). Three tabs (All / Favourites / Archived) and row of
   link chips to web UI and both manga sites; `WEB_BASE` sits in CONFIG
   block next to `API_BASE`. FAB is `7 × 44` edge tab whose *hit* area
   widened to `28 × 72` by invisible `#hit` child; `#fab` must keep
   `touch-action: none` and must **not** regain `overflow: hidden`. Since
   `touch-action` resolved at gesture start, strip can't be both
   browser-scrolled and script-dragged, so `makeDraggable` splits by intent: swipe
   from `#hit` scrolls via `window.scrollBy`, hold of `ARM_MS` arms
   reposition drag, visible sliver drags with no hold. See
   `docs/superpowers/specs/2026-07-28-edge-tab-hitbox-design.md`.
6. **SPA navigation** — Asura is Astro, client-routed on comic/chapter pages: patch `history.pushState`/`replaceState` + listen `popstate`, re-run `detect()` on URL change so auto-update fire without reload. Demonic uses classic reloads (initial `document-idle` run suffice).

### Live URL shapes (verified 2026-07-26, may drift — re-check against live pages before trust)

- **asurascans.com**: series `/comics/<slug>` (slug carries trailing
  site-wide build-hash suffix, e.g. `-059befe1`, that **rotates on every
  redeploy**), chapter `/comics/<slug>/chapter/<n>`. `seriesId` must strip
  hash (`/-[0-9a-f]{8}$/`, `stripBuildHash` in userscript,
  `asuraBuildHash` in backend); URLs keep full slug — stale-hash
  URLs 302 to current ones. Astro-rendered; chapter links present in raw
  server HTML.
- **demonicscans.org**: series `/manga/<slug>` (slug may URL-encode punctuation, e.g. `%2527` for `'`), chapter `/title/<slug>/chapter/<n>/<page>` (older `chaptered.php?manga=<id>&chapter=<n>` form still exists as redirect, what series-page chapter-list anchors link through).
  Encodings (incl. triple-encoded punctuation like `%25252D`) identical
  on /manga/ and /title/ pages, so decode-once seriesIds match — verified
  2026-07-28.
- **comix.to**: series `/title/<id>-<slug>`, chapter
  `/title/<id>-<slug>/<uploadId>-chapter-<n>`. Only the leading `<id>` is
  identity — the slug re-renders when a series is renamed (`comixSeriesId`).
  An SPA that **never rewrites `og:title`**: the server-rendered head keeps
  whatever document loaded first, so on a cold load `og:title` is the homepage's
  "Comix — Read Comics online for free" and after an in-page hop it is the
  *previous* series' name. `document.title` is the one thing client routing does
  update, so titles come from there, with the chapter page's `" · Ch.<n>"` tail
  stripped. It publishes no `og:image` either, which is one of the reasons cover
  acquisition moved to the backend.
- **kagane.to**: series `/series/<uuid>`, reader
  `/series/<uuid>/reader/<bookUuid>`. Reader URLs carry no chapter number, so
  the number comes out of `og:title`. Two shapes exist: `"<Series> - Chapter
  <n>[ - Episode <n>]"` and, for volume-numbered series, `"<Series> - Volume <v>
  Chapter <n>"` with no episode name — both must yield a bare series title, or
  the volume tail lands in the bookmark's title.
  Its covers are challenge- and CORP-protected, so nothing outside kagane.to can
  load one directly; the panel renders the backend's own cover address like every
  other Site. Behind a Cloudflare JS challenge, so the backend polls it
  through the headless browser.
- **novelfull.com** (novel script): series `/<slug>.html`, chapter
  `/<slug>/chapter-<n>[-<title-slug>].html`. No `og:*` tags at all — title from
  `h3.title` (series) or `a.truyen-title` (chapter); the script reads no cover.
  Behind a Cloudflare JS challenge no TLS fingerprint
  clears, so the backend polls it through the headless browser.
- **lightnovelworld.net** (novel script): series `/novel/<slug>/`, chapter
  `/<slug>-chapter-<n>/` — flat, at the site root. The chapter path's slug is a
  Chapter Slug, not an identity: the Series address is read off the page's
  `a[aria-label='All Chapter']` (fallback: the BreadcrumbList's second crumb),
  and a Series may publish under several Chapter Slugs. A chapter page with no
  pointer resolves to `other`, so no Bookmark is offered. `h1.entry-title` is
  the clean title on a series page and `<Title> Chapter <n>` on a chapter page.
  Its series page lists every chapter with an
  absolute href, so the backend polls it with the plain TLS client.
  The client performs no latest-chapter scan for this Site: the Poll's
  one-hour cooldown dominates the client's four-hour throttle, so a scan
  would add no freshness, and the page's wpdiscuz thread is a public write
  surface a scan would have to truncate at. `computeLatestChapter` yields
  null here and `backgroundRefreshLatest` skips the Site before any fetch.

### Second script: `novel-bookmark.user.js`

A copy of the manga script with two adapters, `LIBRARY = "novel"` and
`STORE_PREFIX = "bmgr:novel:"`. No migration loop (this script has no previous
installation to carry keys over from). Installed alongside the manga script;
both write to the same backend with the same `LIBRARY` column discriminating
them.