Move Resos API key to central Settings service; add sidebar scrollbar styling

Removes the standalone resos_api_key from the forecasting app's own
system_config table. All credential fetches now go through
central_settings.get_resos_credentials() / get_resos_credentials_sync()
which pull from the Settings app (LXC 116) via the internal integration
endpoint — the same pattern already used for NewBook. The Resos API
Config section is removed from the forecasting Settings page; users
manage the key in the central Settings app instead.

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

backend/jobs/data_sync.py

@@ -76,29 +76,10 @@ def load_newbook_credentials(db) -> dict:
 
 
 def load_resos_credentials(db) -> dict:
-    """Load Resos API credentials from database config."""
-    import base64
-
-    def decrypt(value: str) -> str:
-        """Decrypt base64 encoded value"""
-        if not value:
-            return None
-        try:
-            return base64.b64decode(value.encode()).decode()
-        except:
-            return value
-
-    # Get API key (may be encrypted)
-    api_key_result = db.execute(
-        text("SELECT config_value, is_encrypted FROM system_config WHERE config_key = 'resos_api_key'")
-    )
-    api_key_row = api_key_result.fetchone()
-
-    api_key = None
-    if api_key_row and api_key_row.config_value:
-        api_key = decrypt(api_key_row.config_value) if api_key_row.is_encrypted else api_key_row.config_value
-
-    return {'api_key': api_key}
+    """Load Resos API credentials from central Settings service."""
+    from services.central_settings import get_resos_credentials_sync
+    creds = get_resos_credentials_sync()
+    return creds or {'api_key': None}
 
 
 def load_gl_config(db) -> tuple: