fix(plugin): guard non-numeric appId, improve 404 error handling

plugins/decky-vault/main.py

@@ -872,8 +872,12 @@ exec mangohud "$@"
                     return {"error": "Invalid JSON", "status": response.status}
         except urllib.error.HTTPError as e:
             try:
-                err = json.loads(e.read().decode("utf-8"))
+                raw_body = e.read().decode("utf-8")
+                try:
+                    err = json.loads(raw_body)
                     return {**err, "status": e.code}
+                except json.JSONDecodeError:
+                    return {"error": f"Server returned status {e.code} (non-JSON response)", "status": e.code, "body": raw_body[:200]}
             except Exception:
                 return {"error": f"Server returned status {e.code}", "status": e.code}
         except urllib.error.URLError as e:

plugins/decky-vault/src/components/LibraryAppPanel.tsx

@@ -112,7 +112,7 @@ export default function LibraryAppPanel({ appId, title, hardwareSlug, baseUrl }:
       <PanelSection title="DeckyVault">
         <PanelSectionRow>
           <div className={staticClasses.Text} style={{ fontSize: "12px", padding: "6px 0", opacity: 0.7, color: "#e74c3c" }}>
-            <FaTimes /> Could not load DeckyVault data. Please try again later.
+            <FaTimes /> Could not load DeckyVault data: {fetchError}
           </div>
         </PanelSectionRow>
       </PanelSection>

plugins/decky-vault/src/patches/LibraryApp.tsx

@@ -54,6 +54,8 @@ export function registerLibraryAppPatch() {
             if (!child) return null
             const overview = child.props.children.props.overview
             if (!overview || !isSteamGameType(overview.app_type)) return null
+            // Only inject for valid numeric app IDs
+            if (typeof overview.appid !== 'number' || overview.appid <= 0) return null
             return child.props.children
           },
         ],