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>

packages/tasks/manifest.json

@@ -0,0 +1,74 @@
+{
+  "id": "tasks",
+  "title": "Tasks",
+  "type": "full",
+  "tier": "starlark",
+  "route": "/s/tasks",
+  "auth": "authenticated",
+  "layout": "single",
+  "version": "0.1.0",
+  "icon": "✅",
+  "description": "Task management surface with lifecycle events, webhook integration, and scheduled reminders.",
+  "author": "switchboard",
+
+  "permissions": ["db.write", "notifications.send"],
+
+  "api_routes": [
+    {"method": "GET",    "path": "/items"},
+    {"method": "POST",   "path": "/items"},
+    {"method": "GET",    "path": "/items/*"},
+    {"method": "PUT",    "path": "/items/*"},
+    {"method": "DELETE", "path": "/items/*"},
+    {"method": "GET",    "path": "/stats"}
+  ],
+
+  "db_tables": {
+    "items": {
+      "columns": {
+        "title":        "text",
+        "description":  "text",
+        "status":       "text",
+        "priority":     "text",
+        "assignee_id":  "text",
+        "creator_id":   "text",
+        "due_date":     "text",
+        "tags":         "text",
+        "updated_at":   "text",
+        "completed_at": "text"
+      },
+      "indexes": [
+        ["status"],
+        ["assignee_id"],
+        ["creator_id"]
+      ]
+    }
+  },
+
+  "triggers": [
+    {
+      "type": "event",
+      "pattern": "task.*",
+      "entry_point": "on_task_event"
+    },
+    {
+      "type": "webhook",
+      "slug": "create",
+      "entry_point": "on_webhook"
+    }
+  ],
+
+  "settings": {
+    "statuses": {
+      "type": "string",
+      "label": "Statuses",
+      "description": "Comma-separated task statuses",
+      "default": "todo,in_progress,done,cancelled"
+    },
+    "priorities": {
+      "type": "string",
+      "label": "Priorities",
+      "description": "Comma-separated task priorities",
+      "default": "low,medium,high,urgent"
+    }
+  }
+}