Movie Editor: make Reset Studio session a toggle (disarmable)

Clicking 'Reset Studio session' again now cancels a pending reset (mis-click safe);
the menu shows 'armed — click to cancel' when set.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

movie_editor/frontend/menubar.js

@@ -87,7 +87,7 @@
         { label: "Refresh model list", hint: "R", action: async () => { try { await window.MovieEditorAPI.refreshModels(); } catch (_) {} } },
       ],
       FunPack: [
-        { label: st.resetSessionArmed ? "Reset Studio session ✓ (armed)" : "Reset Studio session",
+        { label: st.resetSessionArmed ? "Reset Studio session ✓ armed — click to cancel" : "Reset Studio session",
           disabled: !hasProject(), action: () => S.resetStudioSession() },
         { sep: true },
         { menulabel: "Libraries (in ComfyUI Studio)" },

movie_editor/frontend/store.js

@@ -420,11 +420,12 @@
     });
   }
 
-  // Arm a Studio session reset — applied to the FIRST run of the next generation.
+  // Toggle a pending Studio session reset — applied to the FIRST run of the next
+  // generation. Clicking again disarms it (in case of a mis-click).
   let _resetSessionPending = false;
   function resetStudioSession() {
-    _resetSessionPending = true;
-    set({ resetSessionArmed: true });
+    _resetSessionPending = !_resetSessionPending;
+    set({ resetSessionArmed: _resetSessionPending });
   }
 
   // Generate one run (single scene, or an explicit list of scene ids). Returns success.