Fix comprehensive system issues and implement proper vector database backend selection

- Fix remaining datetime timezone errors across all database operations
- Implement dynamic vector database backend (Qdrant/ChromaDB) based on install.py configuration
- Add LLM timeout handling with immediate fallback responses for slow self-hosted models
- Use proper install.py configuration (2000 max tokens, 5min timeout, correct LLM endpoint)
- Fix PostgreSQL schema to use timezone-aware columns throughout
- Implement async LLM request handling with background processing
- Add configurable prompt limits and conversation history controls
- Start missing database services (PostgreSQL, Redis) automatically
- Fix environment variable mapping between install.py and application code
- Resolve all timezone-naive vs timezone-aware datetime conflicts

System now properly uses Qdrant vector database as specified in install.py instead of hardcoded ChromaDB.
Characters respond immediately with fallback messages during long LLM processing times.
All database timezone errors resolved with proper timestamptz columns.

src/main.py

@@ -168,6 +168,10 @@ class FishbowlApplication:
             await self.scheduler.start()
             logger.info("Conversation scheduler started")
             
+            # Start LLM cleanup task
+            cleanup_task = asyncio.create_task(self._llm_cleanup_loop())
+            logger.info("LLM cleanup task started")
+            
             # Start Discord bot
             bot_task = asyncio.create_task(
                 self.discord_bot.start(self.settings.discord.token)
@@ -181,7 +185,7 @@ class FishbowlApplication:
             
             # Wait for shutdown signal or bot completion
             done, pending = await asyncio.wait(
-                [bot_task, asyncio.create_task(self.shutdown_event.wait())],
+                [bot_task, cleanup_task, asyncio.create_task(self.shutdown_event.wait())],
                 return_when=asyncio.FIRST_COMPLETED
             )
             
@@ -239,6 +243,24 @@ class FishbowlApplication:
         # On Windows, handle CTRL+C
         if os.name == 'nt':
             signal.signal(signal.SIGBREAK, signal_handler)
+    
+    async def _llm_cleanup_loop(self):
+        """Background task to clean up completed LLM requests"""
+        try:
+            while not self.shutdown_event.is_set():
+                await llm_client.cleanup_pending_requests()
+                pending_count = llm_client.get_pending_count()
+                
+                if pending_count > 0:
+                    logger.debug(f"LLM cleanup: {pending_count} pending background requests")
+                
+                # Wait 30 seconds before next cleanup
+                await asyncio.sleep(30)
+                
+        except asyncio.CancelledError:
+            logger.info("LLM cleanup task cancelled")
+        except Exception as e:
+            logger.error(f"Error in LLM cleanup loop: {e}")
 
 async def main():
     """Main entry point"""