Add Bookmarks example plugin

Adds packages/plugins/examples/plugin-bookmarks-example, a new first-party
"core surface" example that exercises plugin database namespaces, local
folders, scoped API routes, and the page/sidebar/dashboard/settings UI
slots end-to-end. Registers the example as a bundled plugin in
server/src/routes/plugins.ts and excludes its workspace importer in
pnpm-workspace.yaml so PRs don't have to commit lockfile entries for it.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/plugins/examples/plugin-bookmarks-example/tsconfig.json

@@ -0,0 +1,27 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "lib": [
+      "ES2022",
+      "DOM"
+    ],
+    "jsx": "react-jsx",
+    "strict": true,
+    "skipLibCheck": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "outDir": "dist",
+    "rootDir": "."
+  },
+  "include": [
+    "src",
+    "tests"
+  ],
+  "exclude": [
+    "dist",
+    "node_modules"
+  ]
+}