Feat v0.2.4: SDK Topbar, Schedules surface, manifest icons, UserMenu cleanup

Shell navigation:
- sw.shell.Topbar — composable nav bar (title + slot + bell + user menu)
- Topbar CSS in sw-shell.css, wired into SDK via dynamic import

Schedules surface (packages/schedules/):
- Wraps kernel /api/v1/schedules CRUD + run + logs
- Table view with cron badge, human-readable preview, enable toggle
- Create/edit dialog with live cron-to-english preview

Manifest icons:
- icon field in manifest.json (emoji string)
- Surfaces API returns icon from package manifest
- UserMenu renders per-surface icons

UserMenu cleanup:
- Removed dead Chat/Notes/Projects hardcoded links
- Menu now driven by /api/v1/surfaces API (installed surfaces only)
- Core surfaces filtered via CORE_IDS set

Bug fixes:
- isAdmin() in can.js now checks surface.admin.access RBAC grant
  instead of deprecated user.role column (v0.2.0 regression)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/js/sw/sdk/actions.js

@@ -0,0 +1,70 @@
+// ==========================================
+// Switchboard Core — SDK: Action Registry
+// ==========================================
+// Named actions that extensions expose for invocation.
+//
+// Factory: createActions(emitFn)
+// ==========================================
+
+/**
+ * Create the action registry.
+ *
+ * @param {Function} emitFn — events.emit for notifications
+ * @returns {object} actions
+ */
+export function createActions(emitFn) {
+    /** @type {Map<string, {handler:Function, label?:string, icon?:string}>} */
+    const _registry = new Map();
+
+    return {
+        /**
+         * Register a named action.
+         * @param {string} id — unique action id (e.g. 'tasks.create')
+         * @param {object} def — { handler, label?, icon? }
+         * @returns {Function} unregister
+         */
+        register(id, { handler, label, icon }) {
+            _registry.set(id, { handler, label, icon });
+            emitFn('action.registered', { id, label }, { localOnly: true });
+            return () => this.unregister(id);
+        },
+
+        /**
+         * Remove an action.
+         */
+        unregister(id) {
+            if (_registry.delete(id)) {
+                emitFn('action.unregistered', { id }, { localOnly: true });
+            }
+        },
+
+        /**
+         * Execute an action by id.
+         * @param {string} id
+         * @param {...any} args — passed to handler
+         * @returns {Promise<any>}
+         */
+        async run(id, ...args) {
+            const entry = _registry.get(id);
+            if (!entry) throw new Error(`[sw.actions] Unknown action: ${id}`);
+            const result = await entry.handler(...args);
+            emitFn('action.executed', { id }, { localOnly: true });
+            return result;
+        },
+
+        /**
+         * List registered action metadata.
+         * @returns {Array<{id:string, label?:string, icon?:string}>}
+         */
+        list() {
+            return [..._registry.entries()].map(([id, { label, icon }]) => ({ id, label, icon }));
+        },
+
+        /**
+         * Check if an action is registered.
+         */
+        has(id) {
+            return _registry.has(id);
+        },
+    };
+}