fix(dashboard): replace broken Rulează Ralph on idle cards with Propose

The idle-state action called /api/projects/approve, which 404'd because
idle workspace dirs have no approved-tasks.json entry to mutate. Now the
button opens the Propose modal pre-filled with the workspace slug so the
user actually has a path forward.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

dashboard/workspace.html

@@ -1331,7 +1331,7 @@
                     ];
                 case 'idle':
                     return [
-                        { label: 'Rulează Ralph', type: 'secondary', action: () => approveProject(slug) },
+                        { label: 'Propune feature', type: 'secondary', action: () => openProposeModal(slug) },
                         { label: 'Șterge',          type: 'ghost',     action: () => confirmDeleteIdle(slug) },
                     ];
                 default:
@@ -1655,12 +1655,13 @@
             proposeDesc.classList.remove('is-invalid');
         }
 
-        function openProposeModal() {
+        function openProposeModal(prefilledSlug) {
             clearProposeErrors();
-            proposeSlug.value = '';
+            proposeSlug.value = prefilledSlug || '';
             proposeDesc.value = '';
             proposeWithPlanning.checked = true;
-            openModal(proposeModal, { focusSelector: '#proposeSlug' });
+            const focusSel = prefilledSlug ? '#proposeDesc' : '#proposeSlug';
+            openModal(proposeModal, { focusSelector: focusSel });
         }
 
         function requestCloseProposeModal() {