feat: Phase 1 autonomy upgrades — introspection, heartbeat, source tagging, Discord auto-detect (#101)

UC-01: Live System Introspection Tool
- Add get_task_queue_status(), get_agent_roster(), get_live_system_status()
  to timmy/tools_intro with graceful degradation
- Enhanced get_memory_status() with line counts, section headers, vault
  directory listing, semantic memory row count, self-coding journal stats
- Register system_status MCP tool (creative/tools/system_status.py)
- Add system_status to Timmy's tool list + Hard Rule #7

UC-02: Fix Offline Status Bug
- Add registry.heartbeat() calls in task_processor run_loop() and
  process_single_task() so health endpoint reflects actual agent status
- health.py now consults swarm registry instead of Ollama connectivity

UC-03: Message Source Tagging
- Add source field to Message dataclass (default "browser")
- Tag all message_log.append() calls: browser, api, system
- Include source in /api/chat/history response

UC-04: Discord Token Auto-Detection & Docker Fix
- Add _discord_token_watcher() background coroutine that polls every 30s
  for DISCORD_TOKEN in env vars, .env file, or state file
- Add --extras discord to all three Dockerfiles (main, dashboard, test)

All 26 Phase 1 tests pass in Docker (make test-docker).
Full suite: 1889 passed, 77 skipped, 0 failed.

Co-authored-by: Alexander Payne <apayne@MM.local>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -27,7 +27,7 @@ RUN pip install --no-cache-dir poetry poetry-plugin-export
 COPY pyproject.toml poetry.lock ./
 
 # Export pinned requirements and install with pip cache mount
-RUN poetry export --extras swarm --extras telegram --without-hashes \
+RUN poetry export --extras swarm --extras telegram --extras discord --without-hashes \
         -f requirements.txt -o requirements.txt
 
 RUN --mount=type=cache,target=/root/.cache/pip \