Add API usage tracking and dynamic task reloading

Features:
- Usage tracking system (usage_tracker.py)
  - Tracks input/output tokens per API call
  - Calculates costs with support for cache pricing
  - Stores data in usage_data.json (gitignored)
  - Integrated into llm_interface.py

- Dynamic task scheduler reloading
  - Auto-detects YAML changes every 60s
  - No restart needed for new tasks
  - reload_tasks() method for manual refresh

- Example cost tracking scheduled task
  - Daily API usage report
  - Budget tracking ($5/month target)
  - Disabled by default in scheduled_tasks.yaml

Improvements:
- Fixed tool_use/tool_result pair splitting bug (CRITICAL)
- Added thread safety to agent.chat()
- Fixed N+1 query problem in hybrid search
- Optimized database batch queries
- Added conversation history pruning (50 messages max)

Updated .gitignore:
- Exclude user profiles (memory_workspace/users/*.md)
- Exclude usage data (usage_data.json)
- Exclude vector index (vectors.usearch)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

adapters/runtime.py

@@ -84,8 +84,20 @@ class AdapterRuntime:
         self._postprocessors.append(postprocessor)
 
     def _on_message_received(self, message: InboundMessage) -> None:
-        """Handle incoming message from an adapter."""
-        asyncio.create_task(self._message_queue.put(message))
+        """Handle incoming message from an adapter.
+
+        This may be called from different event loop contexts (e.g.,
+        python-telegram-bot's internal loop vs. our main asyncio loop),
+        so we use loop-safe scheduling instead of create_task().
+        """
+        try:
+            loop = asyncio.get_running_loop()
+            loop.call_soon_threadsafe(self._message_queue.put_nowait, message)
+        except RuntimeError:
+            # No running loop - should not happen in normal operation
+            # but handle gracefully
+            print("[Runtime] Warning: No event loop for message dispatch")
+            self._message_queue.put_nowait(message)
 
     async def _process_message_queue(self) -> None:
         """Background task to process incoming messages."""