Feat v0.4.2 tags search

Tags table (ext_notes_tags), tag CRUD API, tag filtering in sidebar,
tag pills on note cards, drag-and-drop note-to-folder moves, folder
context menu replacing prompt() hack. Notes package bumped to v0.3.0.

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

packages/notes/manifest.json

@@ -6,7 +6,7 @@
   "route": "/s/notes",
   "auth": "authenticated",
   "layout": "single",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "icon": "📝",
   "description": "Markdown notes surface with folders, tags, and backlinks.",
   "author": "switchboard",
@@ -25,7 +25,10 @@
     {"method": "POST",   "path": "/folders"},
     {"method": "PUT",    "path": "/folders/*"},
     {"method": "DELETE", "path": "/folders/*"},
-    {"method": "POST",   "path": "/notes/move"}
+    {"method": "POST",   "path": "/notes/move"},
+    {"method": "GET",    "path": "/tags"},
+    {"method": "GET",    "path": "/tags/*"},
+    {"method": "PUT",    "path": "/tags/*"}
   ],
 
   "db_tables": {
@@ -46,6 +49,16 @@
         ["updated_at"]
       ]
     },
+    "tags": {
+      "columns": {
+        "note_id": "text",
+        "tag":     "text"
+      },
+      "indexes": [
+        ["note_id"],
+        ["tag"]
+      ]
+    },
     "folders": {
       "columns": {
         "name":       "text",