harness: a resume mode (autoplay blocked); docs for the state machine and hooks

tools/harness.sh resume seeds IndexedDB with a station and one rendered
track, resumes it with no user gesture and expects the TAP TO PLAY wait.
IndexedDB needs http, so the page is served from a temp folder; headless
Chrome's virtual time doesn't wait for IndexedDB, so this mode is driven in
real time over the DevTools protocol (tools/harness-cdp.py, stdlib only).
The loop harness now prints state.phase too.

ARCHITECTURE.md describes the machine as implemented; HANDOFF.md lists what
was found and left alone; STORAGE.md gains db.get and the tapes store (the
code already had both); README points at the new files.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K6897PWcUEwHiqZMcVnNF6

README.md

@@ -19,12 +19,14 @@ browser (IndexedDB) — see STORAGE.md.
 
 ## Files
 
-- `index.html` — the whole app: markup, styles, and the player, station, library, tapes, breaks, covers, sheets.
+- `index.html` — the whole app: markup, styles, and the player (a small state machine), station, library, tapes,
+  breaks, covers, sheets, and the `hooks` brain.js plugs into.
 - `brain.js` — the taste model (a small net per station and overall), the TASTE screen, the DJ's taste text.
 - `sw.js` — service worker: caches the shell; stamped with the commit by the shots workflow.
 - `manifest.json`, `icons/`, `favicon.svg` — PWA. Icons are drawn by `tools/icons.py` (stdlib only).
 - `tools/shots.sh` — the card image and the icons, run by `.gitea/workflows/shots.yml` on every push.
-- `tools/harness.sh` + `tools/harness.html` — the playback regression harness (ARCHITECTURE.md › Testing).
+- `tools/harness.sh` + `tools/harness.html` (the station loop) + `tools/harness-resume.html` and `tools/harness-cdp.py`
+  (resume with autoplay blocked) — the playback regression harness (ARCHITECTURE.md › Testing).
 - `STORAGE.md` — the IndexedDB contract. `ARCHITECTURE.md` — how it all fits. `HANDOFF.md` — read before changing things.
 
 ## Backend