feat(release): manifest-driven screenshot capture with fail-closed mock-data guards (#1261)

Third slice of the release-notes pipeline (#1256 format+generator, #1257 CI
gate): release screenshots become reproducible and provably mock-only.

The v0.20 capture script was single-use (hard-coded slugs, paths, hero) and
fail-open: a lost IPTVNATOR_E2E_DATA_DIR silently fell back to the user's
real ~/.iptvnator database, `...process.env` leaked ambient TMDB keys and
proxies, nothing gated network access, and no frame content was ever
validated. Each hole leaks real playlists, credentials, or copyrighted
artwork into published screenshots without a single signal.

New pipeline:

- tools/release/screenshots.manifest.json — declarative shots (slug, title,
  named setup steps, themes). Adding a feature shot = one manifest entry.
- capture-release-screenshots.ts — orchestrator; output goes to
  apps/website/public/blog/<release>/screenshots/<slug>-<theme>.png, release
  slug derived from package.json (or --release), --only/--theme filters.
- capture-app-driver.ts / capture-navigation.ts — launch, seeding, theme,
  and the named-action vocabulary; actions are order-independent (every
  portal action starts from the dashboard).
- screenshot-guards.mjs — the fail-closed policy, pure and unit-tested:
  G1 the real database is snapshotted (sha256+mtime) before launch and must
     be byte-identical after; the isolated DB must actually exist
  G2 the app receives an allowlisted environment, never ...process.env
  G3 deny-by-default network gate; known app-level calls (GitHub update
     check) are answered by local stubs; any other blocked request fails
     the run — a silently-blocked TMDB call would leave a frame that looks
     broken rather than unsafe
  G4 every frame is scanned before capture: external img/background URLs,
     credential-shaped text, MAC addresses, non-localhost m3u8 references
  G5 TMDB enrichment asserted disabled via the renderer's IndexedDB
  Any violation deletes every frame captured in the run and exits non-zero.

The guards paid for themselves on the first live run: G3 caught the mock
server redirecting stream endpoints to a public demo HLS
(test-streams.mux.dev) — meaning earlier hand-run captures could embed
third-party video frames. The M3U shot now deliberately captures the groups
layout without starting playback.

`.changes` validation now cross-checks `screenshot:` slugs against the
manifest, so a note cannot reference an image the capture run never
produces.

Verified end-to-end: 10/10 shots (5 slugs × dark/light) captured against
dist build + xtream-mock-server, frames visually inspected (fictional
titles/artwork only), guard-violation paths exercised live. 67 unit tests
in release-tools, lint green, script files within the repo size limit.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

.codex/skills/release-cut/SKILL.md

@@ -42,11 +42,21 @@ is not optional.
     for a patch release, edit the existing post (the scaffold refuses to
     overwrite without `--force`).
 
-5. **Screenshots** — only from the release capture script against the mock
-   servers (`tools/release/`), never from a real playlist or account: real
-   streams, logos, and TMDB artwork are copyrighted, and credentials must
-   never reach a published image. Output goes to
-   `apps/website/public/blog/v0-XX/screenshots/`.
+5. **Screenshots** — only from the fail-closed capture script against the
+   mock servers, never from a real playlist or account: real streams, logos,
+   and TMDB artwork are copyrighted, and credentials must never reach a
+   published image.
+
+    ```bash
+    pnpm nx run electron-backend:build-e2e   # once
+    pnpm run release:screenshots             # all manifest shots, dark+light
+    ```
+
+    Output goes to `apps/website/public/blog/v0-XX/screenshots/`. New feature
+    to showcase = new entry in `tools/release/screenshots.manifest.json`
+    (slug must match the note's `screenshot:` field). The run aborts and
+    deletes its frames on any guard violation (real-DB touch, external
+    request, credential-shaped text in frame, TMDB active).
 
 6. **Consume the notes** (the only destructive step):