refactor: move studio to frontends workspace

- Move studio from root to frontends/studio/
- Add owner-tools frontend for live blog admin UI
- Add shared ui component library
- Set up npm workspaces for frontends
- Add enhanced code block extension for editor

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontends/ui/package.json

@@ -0,0 +1,27 @@
+{
+  "name": "@writekit/ui",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "exports": {
+    ".": "./src/index.ts",
+    "./uno.config": "./uno.config.ts",
+    "./styles": "./src/styles.ts"
+  },
+  "scripts": {
+    "build": "echo 'no build needed - consumed as source'",
+    "typecheck": "tsc --noEmit"
+  },
+  "dependencies": {
+    "unocss": "^66.5.12"
+  },
+  "devDependencies": {
+    "@iconify-json/lucide": "^1.2.82",
+    "@types/react": "^19.0.0",
+    "react": "^19.0.0",
+    "typescript": "^5.7.0"
+  },
+  "peerDependencies": {
+    "react": "^19.0.0"
+  }
+}