docs: comprehensive doc audit — sync all docs to current state

- MASTER.md: tool count 40→47, add proactive notifications + spawn_agent rows, date bump
- ROADMAP.md: mark local orchestrator/web push/proactive notifs/spawn_agent/web_read/session_read as done, date bump
- ARCH__CHANNELS.md: rewrite notification channel config section — all 4 channels, all triggers, on-demand endpoints
- ARCH__SYSTEM.md: update tools/ module list to include files, agents
- README.md: update LLM backends in architecture diagram, add browser push to channels table
- CLAUDE.md: add doc update checklist to Documentation Philosophy section

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -182,10 +182,10 @@ Back it up separately — it is required to restore from any snapshot.
     └─ POST /channels/google-chat/{username} — Google Chat Add-on (per-user)
         ↓
   LLM Backends
-  • Claude CLI   — primary, all user-facing responses
-  • Gemini CLI   — fallback
-  • Gemini API   — orchestrator tool loop only (not general chat)
-  • Local        — Open WebUI/Ollama on scott_gaming (private/offline)
+  • Claude CLI      — primary, all user-facing responses
+  • Gemini CLI      — fallback
+  • Gemini API      — orchestrator tool loop (two-brain: Gemini plans, Claude responds)
+  • Local OpenAI    — Open WebUI/Ollama on scott_gaming; also runs local orchestrator loop
         ↓
   Persona context loaded from home/{user}/persona/{name}/
 ```
@@ -213,11 +213,12 @@ Context is loaded at request time from `home/{user}/persona/{name}/` via `cortex
 
 Webhook endpoints are per-user — each user configures their own secrets in `home/{username}/channels.json`.
 
-| Channel | Status | Endpoint |
+| Channel | Status | Endpoint / Notes |
 |---|---|---|
 | Web UI | Live | `https://cortex.dgrzone.com` — session auth (login form + JWT cookie) |
 | Nextcloud Talk | Live | `POST /webhook/nextcloud/{username}` — HMAC-signed, async reply |
 | Google Chat | Live | `POST /channels/google-chat/{username}` — Workspace Add-on, JWT auth |
+| Browser Push | Live | VAPID push notifications — subscribe via ☰ menu; proactive reminders + distill alerts |
 
 See `docs/NEXTCLOUD_TALK_BOT.md` and `docs/GOOGLE_CHAT_BOT.md` for setup instructions.