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>

src/dashboard/routes/chat_api.py

@@ -84,16 +84,16 @@ async def api_chat(request: Request):
             session_id="mobile",
         )
 
-        message_log.append(role="user", content=last_user_msg, timestamp=timestamp)
-        message_log.append(role="agent", content=response_text, timestamp=timestamp)
+        message_log.append(role="user", content=last_user_msg, timestamp=timestamp, source="api")
+        message_log.append(role="agent", content=response_text, timestamp=timestamp, source="api")
 
         return {"reply": response_text, "timestamp": timestamp}
 
     except Exception as exc:
         error_msg = f"Timmy is offline: {exc}"
         logger.error("api_chat error: %s", exc)
-        message_log.append(role="user", content=last_user_msg, timestamp=timestamp)
-        message_log.append(role="error", content=error_msg, timestamp=timestamp)
+        message_log.append(role="user", content=last_user_msg, timestamp=timestamp, source="api")
+        message_log.append(role="error", content=error_msg, timestamp=timestamp, source="api")
         return JSONResponse(
             status_code=503,
             content={"error": error_msg, "timestamp": timestamp},
@@ -141,6 +141,7 @@ async def api_chat_history():
                 "role": msg.role,
                 "content": msg.content,
                 "timestamp": msg.timestamp,
+                "source": msg.source,
             }
             for msg in message_log.all()
         ]