cleanup: remove dead server config methods from config_manager

get_server_config() and set_server_config() in ConfigManager had zero
callers — every part of the codebase already uses the server_manager
singleton. Removing them eliminates the risk of a stale write that
bypasses the in-memory cache in ServerManager.

server_manager is now the sole owner of servers_config.json.

bot/config_manager.py

@@ -321,48 +321,6 @@ class ConfigManager:
             self._current_gpu = value
         logger.debug(f"📊 State: {key} = {value}")
 
-    # ========== Server Configuration ==========
-
-    def get_server_config(self, guild_id: int) -> Dict:
-        """Get configuration for a specific server."""
-        server_config_file = self.memory_dir / "servers_config.json"
-        
-        try:
-            if server_config_file.exists():
-                with open(server_config_file, "r") as f:
-                    all_servers = json.load(f)
-                    return all_servers.get(str(guild_id), {})
-        except Exception as e:
-            logger.error(f"❌ Failed to load server config: {e}")
-        
-        return {}
-
-    def set_server_config(self, guild_id: int, config: Dict):
-        """Set configuration for a specific server."""
-        server_config_file = self.memory_dir / "servers_config.json"
-        
-        try:
-            # Load existing config
-            all_servers = {}
-            if server_config_file.exists():
-                with open(server_config_file, "r") as f:
-                    all_servers = json.load(f)
-            
-            # Update server config
-            all_servers[str(guild_id)] = {
-                **all_servers.get(str(guild_id), {}),
-                **config,
-                "last_updated": datetime.now().isoformat()
-            }
-            
-            # Save
-            with open(server_config_file, "w") as f:
-                json.dump(all_servers, f, indent=2)
-            
-            logger.info(f"💾 Saved server config for {guild_id}")
-        except Exception as e:
-            logger.error(f"❌ Failed to save server config: {e}")
-
     # ========== GPU State ==========
 
     def get_gpu(self) -> str: