docs(ui): finalize MVP plan structure and de-archaeologize topic docs

MVP web client (Phases 1-30) is complete; reorganize planning + living docs around that.

- PLAN.md kept as the staged MVP record (1-30) with a status block + pointers; removed the 31-36 stages, regression scenarios, and deferred-TODO section (moved out); fixed a stale cross-machine plan path.

- ui/PLAN-finalize.md (new): active web-finalization plan in 8 stages (visual system, a11y, i18n, error UX, PWA, build hygiene, docs, owner manual-QA loop); absorbs former Phases 33 and 35.

- ui/ROADMAP.md (new): post-MVP (Wails, Capacitor, realistic projection, acceptance + regression scenarios) and triaged deferred follow-ups.

- ui/docs/README.md (new): grouped topic-doc index.

- De-archaeologized all 20 ui/docs topic docs + ui/README.md + ui/core/README.md: stripped Phase-N build history, rewritten as current-state; deferred work now points at ROADMAP.md / PLAN-finalize.md. Docs-only; no code change.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/docs/events.md

@@ -9,9 +9,8 @@ stops it on sign-out.
 
 ## Why a single consumer
 
-Before Phase 24, the watcher in `lib/revocation-watcher.ts` opened a
-parallel stream just to observe session revocation. Phase 24 folds
-that watcher into `EventStream` so that:
+The `EventStream` singleton consolidates what was previously a
+separate revocation watcher in `lib/revocation-watcher.ts` so that:
 
 - there is only **one** SubscribeEvents connection per session
   (avoids doubling the gateway hub load);
@@ -19,7 +18,7 @@ that watcher into `EventStream` so that:
   `Unauthenticated` ConnectError funnel through one
   `session.signOut("revoked")` call site;
 - per-event-type dispatch (turn-ready toasts, lobby/mail/battle
-  notifications later) shares the same verification path.
+  notifications) shares the same verification path.
 
 ## Lifecycle
 
@@ -67,10 +66,9 @@ exponential backoff (base 1 s, ceiling 30 s, unbounded retries).
 - `reconnecting` — transient failure, backoff in flight.
 - `offline` — `navigator.onLine === false` at the moment of failure.
 
-The header connection-state indicator planned in `PLAN.md`
-cross-cutting shell reads this rune; it is not part of Phase 24 but
-the rune is wired now so a later phase can add the dot without
-touching this module.
+The header connection-state indicator reads this rune; the rune is
+wired so a future change can add the indicator dot without touching
+this module.
 
 ## Revocation semantics