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>

documentation/ARCH__SYSTEM.md

@@ -72,7 +72,7 @@ Details: [`ARCH__BACKENDS.md`](ARCH__BACKENDS.md) | [`ARCH__PERSONA.md`](ARCH__P
 | `email_utils.py` | SMTP invite emails |
 | `persona_template.py` | Bootstrap a new persona directory from templates |
 | `routers/` | One file per endpoint group — `chat`, `orchestrator`, `auth`, `files`, `ui`, `settings`, `local_llm`, `distill`, `audit`, `usage`, `push`, `help`, `onboarding`, `auth_google`, `nextcloud_talk`, `google_chat` |
-| `tools/` | Orchestrator tool implementations — `web`, `tasks`, `scratch`, `reminders`, `cron`, `system`, `notify`, `ae_journals`, `ae_tasks`, `agent_notes` |
+| `tools/` | Orchestrator tool implementations — `web` (search/fetch/web_read), `files` (file_read/write/session_read/search), `tasks`, `scratch`, `reminders`, `cron`, `system`, `notify`, `ae_journals`, `ae_tasks`, `agent_notes`, `agents` (spawn_agent) |
 | `static/` | Web UI — `index.html`, `app.js`, `style.css`, `login.html`, `setup.html`, `HELP.md`, `local_llm.html`, `settings.html` |
 | `tests/` | pytest suite |