Update extension system and database migrations

Changes:
- Added CLAUDE.md with project instructions
- Updated extension manifest bindings (TypeScript)
- Regenerated database migrations (consolidated into single migration)
- Updated haex schema with table name handling
- Enhanced extension manager and manifest handling in Rust
- Updated extension store in frontend
- Updated vault.db

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src-tauri/database/migrations/meta/0000_snapshot.json

@@ -1,7 +1,7 @@
 {
   "version": "6",
   "dialect": "sqlite",
-  "id": "bcdd9ad3-a87a-4a43-9eba-673f94b10287",
+  "id": "8dc25226-70f9-4d2e-89d4-f3a6b2bdf58d",
   "prevId": "00000000-0000-0000-0000-000000000000",
   "tables": {
     "haex_crdt_configs": {
@@ -411,7 +411,7 @@
           "name": "entry",
           "type": "text",
           "primaryKey": false,
-          "notNull": true,
+          "notNull": false,
           "autoincrement": false,
           "default": "'index.html'"
         },
@@ -444,6 +444,14 @@
           "notNull": true,
           "autoincrement": false
         },
+        "single_instance": {
+          "name": "single_instance",
+          "type": "integer",
+          "primaryKey": false,
+          "notNull": false,
+          "autoincrement": false,
+          "default": false
+        },
         "haex_timestamp": {
           "name": "haex_timestamp",
           "type": "text",
@@ -619,6 +627,13 @@
           "notNull": true,
           "autoincrement": false
         },
+        "device_id": {
+          "name": "device_id",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true,
+          "autoincrement": false
+        },
         "name": {
           "name": "name",
           "type": "text",