refactor: replace GraphQL/REST with MQTT-only for Unraid server data

All server stats (CPU, RAM, Docker, shares, disks, array) now come
directly from MQTT topics published by the Unraid MQTT Agent. This
eliminates the need for API keys, HTTP polling, and the GraphQL/REST
fallback chain.

- Rewrote unraid_service.py to read from MQTT store (no httpx needed)
- Simplified servers router (no cache, no enrichment hack)
- Added mqtt_prefix field to UnraidServer config
- Updated DB: both Daddelolymp and Adriahub with mqtt_prefix, no api_key
- Data is always fresh (MQTT pushes every ~15s)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/config.py

@@ -19,9 +19,10 @@ logger = logging.getLogger(__name__)
 @dataclass
 class UnraidServer:
     name: str
-    host: str
-    api_key: str = ""
-    port: int = 80
+    host: str = ""
+    mqtt_prefix: str = ""  # MQTT topic prefix, e.g. "Adriahub" or "unraid-daddelolymp"
+    api_key: str = ""  # Deprecated — kept for backward compat
+    port: int = 80  # Deprecated — kept for backward compat
 
 
 @dataclass
@@ -122,11 +123,12 @@ class Settings:
                 UnraidServer(
                     name=srv.get("name", f"Server {i+1}"),
                     host=srv.get("host", ""),
+                    mqtt_prefix=srv.get("mqtt_prefix", ""),
                     api_key=srv.get("api_key", ""),
                     port=int(srv.get("port", 80)),
                 )
                 for i, srv in enumerate(servers_data)
-                if srv.get("host")
+                if srv.get("name") or srv.get("host")
             ]
             s.unraid_enabled = len(s.unraid_servers) > 0
         except (json.JSONDecodeError, TypeError):
@@ -172,11 +174,12 @@ class Settings:
                         UnraidServer(
                             name=s.get("name", ""),
                             host=s.get("host", ""),
+                            mqtt_prefix=s.get("mqtt_prefix", ""),
                             api_key=s.get("api_key", ""),
                             port=int(s.get("port", 80)),
                         )
                         for s in servers
-                        if s.get("host")
+                        if s.get("name") or s.get("host")
                     ]
                     self.unraid_enabled = enabled