Feat v0.4.0 notes surface (#22)

Add Notes as a standard installable surface package (type: full,
tier: starlark). Markdown editor with sidebar note list, live
preview toggle, auto-save, pin/archive, and full-text search.
Zero kernel changes — proves extension stack E2E.

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

packages/notes/manifest.json

@@ -0,0 +1,54 @@
+{
+  "id": "notes",
+  "title": "Notes",
+  "type": "full",
+  "tier": "starlark",
+  "route": "/s/notes",
+  "auth": "authenticated",
+  "layout": "single",
+  "version": "0.1.0",
+  "icon": "📝",
+  "description": "Markdown notes surface with folders, tags, and backlinks.",
+  "author": "switchboard",
+
+  "permissions": ["db.write"],
+
+  "api_routes": [
+    {"method": "GET",    "path": "/notes"},
+    {"method": "POST",   "path": "/notes"},
+    {"method": "GET",    "path": "/notes/*"},
+    {"method": "PUT",    "path": "/notes/*"},
+    {"method": "DELETE", "path": "/notes/*"},
+    {"method": "GET",    "path": "/search"},
+    {"method": "GET",    "path": "/stats"}
+  ],
+
+  "db_tables": {
+    "notes": {
+      "columns": {
+        "title":      "text",
+        "body":       "text",
+        "folder_id":  "text",
+        "creator_id": "text",
+        "updated_at": "text",
+        "pinned":     "int",
+        "archived":   "int"
+      },
+      "indexes": [
+        ["folder_id"],
+        ["creator_id"],
+        ["pinned"],
+        ["updated_at"]
+      ]
+    }
+  },
+
+  "settings": {
+    "default_view": {
+      "type": "string",
+      "label": "Default View",
+      "description": "Default note list view: recent or pinned",
+      "default": "recent"
+    }
+  }
+}