fix: write data under /data and move Firebase creds path to /data; mount static from resolved dirs

app/config.py

@@ -11,7 +11,7 @@ class Settings(BaseSettings):
     ENABLE_APP_CHECK: bool = os.getenv("ENABLE_APP_CHECK", "true").lower() == "true"
     FIREBASE_CREDENTIALS_PATH: str = os.getenv(
         "FIREBASE_CREDENTIALS_PATH",
-        "colorize-662df-firebase-adminsdk-fbsvc-e080668793.json"
+        "/data/firebase-adminsdk.json"
     )
     
     # API settings