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/studio/src/pages/DataPage.tsx

@@ -0,0 +1,106 @@
+import { PageHeader } from '../components/shared'
+import { Icons } from '../components/shared/Icons'
+import { Button } from '../components/ui'
+
+export default function DataPage() {
+  const handleExport = () => {
+    window.location.href = '/api/studio/export'
+  }
+
+  return (
+    <div>
+      <PageHeader />
+
+      {/* Panel container - full-bleed borders */}
+      <div className="-mx-6 lg:-mx-10 mt-6">
+        {/* Import */}
+        <div className="px-6 lg:px-10 py-5">
+          <div className="text-xs font-medium text-muted uppercase tracking-wide">Import</div>
+          <div className="text-xs text-muted mt-0.5">Import posts from other platforms</div>
+        </div>
+        <div className="px-6 lg:px-10 py-6 space-y-4">
+          <div className="p-4 border border-dashed border-border text-center">
+            <Icons.Upload className="text-2xl text-muted mb-2" />
+            <p className="text-sm font-medium mb-1">Upload files</p>
+            <p className="text-xs text-muted mb-3">
+              Supports Markdown files or JSON exports
+            </p>
+            <Button variant="secondary" Icon={Icons.Upload}>
+              Choose Files
+            </Button>
+          </div>
+          <div className="grid grid-cols-1 sm:grid-cols-2 gap-2">
+            <button className="p-3 border border-border text-left hover:border-muted transition-colors">
+              <div className="flex items-center gap-2 mb-1">
+                <Icons.Ghost className="text-muted" />
+                <span className="text-sm font-medium">Ghost</span>
+              </div>
+              <p className="text-xs text-muted">Import from Ghost JSON export</p>
+            </button>
+            <button className="p-3 border border-border text-left hover:border-muted transition-colors">
+              <div className="flex items-center gap-2 mb-1">
+                <Icons.PenTool className="text-muted" />
+                <span className="text-sm font-medium">Substack</span>
+              </div>
+              <p className="text-xs text-muted">Import from Substack export</p>
+            </button>
+            <button className="p-3 border border-border text-left hover:border-muted transition-colors">
+              <div className="flex items-center gap-2 mb-1">
+                <Icons.Posts className="text-muted" />
+                <span className="text-sm font-medium">Markdown</span>
+              </div>
+              <p className="text-xs text-muted">Import Markdown files</p>
+            </button>
+            <button className="p-3 border border-border text-left hover:border-muted transition-colors">
+              <div className="flex items-center gap-2 mb-1">
+                <Icons.WordPress className="text-muted" />
+                <span className="text-sm font-medium">WordPress</span>
+              </div>
+              <p className="text-xs text-muted">Import from WordPress XML</p>
+            </button>
+          </div>
+        </div>
+
+        <div className="border-t border-border" />
+
+        {/* Export */}
+        <div className="px-6 lg:px-10 py-5">
+          <div className="text-xs font-medium text-muted uppercase tracking-wide">Export</div>
+          <div className="text-xs text-muted mt-0.5">Download all your blog data</div>
+        </div>
+        <div className="px-6 lg:px-10 py-6 space-y-3">
+          <p className="text-sm text-muted">
+            Export all your posts, settings, and assets as a ZIP file. This includes:
+          </p>
+          <ul className="text-sm text-muted space-y-1 list-disc list-inside">
+            <li>All posts as Markdown files</li>
+            <li>Settings as JSON</li>
+            <li>Uploaded images and assets</li>
+          </ul>
+          <Button variant="secondary" Icon={Icons.Download} onClick={handleExport}>
+            Export All Data
+          </Button>
+        </div>
+
+        <div className="border-t border-border" />
+
+        {/* Danger Zone */}
+        <div className="px-6 lg:px-10 py-5">
+          <div className="text-xs font-medium text-muted uppercase tracking-wide">Danger Zone</div>
+          <div className="text-xs text-muted mt-0.5">Irreversible actions</div>
+        </div>
+        <div className="px-6 lg:px-10 py-6">
+          <div className="p-4 border border-danger/30 bg-danger/5">
+            <h4 className="text-sm font-medium text-danger mb-2">Delete All Content</h4>
+            <p className="text-xs text-muted mb-3">
+              Permanently delete all posts and assets. This cannot be undone.
+            </p>
+            <Button variant="danger" Icon={Icons.Trash}>
+              Delete All Content
+            </Button>
+          </div>
+        </div>
+      </div>
+    </div>
+  )
+}