feat: add civitai_api_key to config

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

config.json

@@ -1,5 +1,6 @@
 {
     "remote_url": "http://192.168.1.3:8188",
     "timeout": 30,
-    "path_mappings": {}
+    "path_mappings": {},
+    "civitai_api_key": ""
 }

config.py

@@ -19,6 +19,7 @@ class RemoteConfig:
         self.remote_url: str = ""
         self.timeout: int = 30
         self.path_mappings: dict[str, str] = {}
+        self.civitai_api_key: str = ""
         self._load()
 
     # ------------------------------------------------------------------
@@ -35,6 +36,7 @@ class RemoteConfig:
                 self.remote_url = data.get("remote_url", "")
                 self.timeout = int(data.get("timeout", 30))
                 self.path_mappings = data.get("path_mappings", {})
+                self.civitai_api_key = data.get("civitai_api_key", "")
             except Exception as exc:
                 logger.warning("[LM-Remote] Failed to read config.json: %s", exc)
 
@@ -44,6 +46,10 @@ class RemoteConfig:
         if env_timeout:
             self.timeout = int(env_timeout)
 
+        env_api_key = os.environ.get("LM_CIVITAI_API_KEY", "")
+        if env_api_key:
+            self.civitai_api_key = env_api_key
+
         # Strip trailing slash
         self.remote_url = self.remote_url.rstrip("/")