feat(replay): standalone reviewer-gate replay server on :5333

Reproduces the real reviewer UI for any recorded session, with no VPN/Pi/
Python/DWH. The server (node:http, zero deps) serves the built SPA and a
tiny SSE/REST shim that re-emits the reviewer gates captured in a Pi
transcript, in their original order, with the reviewer's real 3-Jul
choices shown as comparison badges.

- tools/replay/extract.mjs: extracts gates from one or many transcripts
  (session-id, file, or directory). Handles sessions split across resume
  re-entries by sorting on message timestamp and dropping unanswered
  gates. Reads the question from session_manifest.yaml, resolving the
  sessions dir from any workspace yaml (no hardcoded paths).
- tools/replay/server.mjs: same-origin :5333. SSE streams gates; POST
  /response advances the cursor and pushes info badges (scelta reale).
  POST /resume and the final "Ripeti/Esci" widget close the SSE so the
  browser EventSource reconnects (cursor resets, gate 1 re-emitted) — the
  replay is re-runnable any number of times. GET /sessions/:id/documents
  reads the real session files so GateArtifactBody resolves file-reference
  artifacts. Exit emits system_event {event:"session_exit"} to return to
  the landing.
- scripts/replay.sh: launcher (extract / build / run / all).
- tools/replay/README.md: data flow, commands, fidelity notes.
- .gitignore: ignore tools/replay/web/ (built artifact, like dist/).

.gitignore

@@ -21,6 +21,9 @@ build/
 # === Node ===
 node_modules/
 
+# === Replay bundle (built artifact, like dist/) ===
+tools/replay/web/
+
 # === Secrets — NEVER commit ===
 .env
 *.pem