feat(studio): temporal source bucket + provenance pill on store grid

Adds the missing UI surface for SPARK / Temporal federated
capabilities. Previously only mcp and n8n showed provenance
pills; temporal-sourced entries fell through to the default
"no badge" case.

  - storeSourceTemporal + storeProvenanceTemporal l10n keys
    (en + de). Pill format: "temporal · <provider>", icon
    Icons.timer_outlined, accent tone.
  - Source filter chip row gains a "Temporal" option in the
    Store filter dialog.
  - `_StoreProvenancePill` adds a `case 'temporal'` branch.

Operators federating a SPARK cluster (`services: -
kind: temporal`) now see their workflows visually labelled
as Temporal-sourced in the Store grid + filter UI.

dart analyze green. No test changes required — the
provenance pill is render-only.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/l10n/app_localizations.dart

@@ -3565,6 +3565,18 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Pull failed: {error}'**
   String systemAiPullFailedError(String error);
+
+  /// No description provided for @storeProvenanceTemporal.
+  ///
+  /// In en, this message translates to:
+  /// **'temporal · {provider}'**
+  String storeProvenanceTemporal(String provider);
+
+  /// No description provided for @storeSourceTemporal.
+  ///
+  /// In en, this message translates to:
+  /// **'Temporal'**
+  String get storeSourceTemporal;
 }
 
 class _AppLocalizationsDelegate