feat(ext/vault): scaffold vault.html tab with sidebar+pane layout and hash routing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

extension/webpack.config.js

@@ -7,6 +7,7 @@ module.exports = {
     popup: './src/popup/popup.ts',
     content: './src/content/detector.ts',
     setup: './src/setup/setup.ts',
+    vault: './src/vault/vault.ts',
   },
   output: {
     path: path.resolve(__dirname, 'dist'),
@@ -27,6 +28,8 @@ module.exports = {
         { from: 'src/popup/styles.css', to: 'styles.css' },
         { from: 'setup.html', to: '.' },
         { from: 'icons', to: 'icons' },
+        { from: 'src/vault/vault.html', to: 'vault.html' },
+        { from: 'src/vault/vault.css', to: 'vault.css' },
         { from: 'wasm/relicario_wasm_bg.wasm', to: '.' },
         { from: 'wasm/relicario_wasm.js', to: '.' },
       ],