build(editor): blog editor JS build and drift gate

- Private ESM package with exact pins: @tiptap/core, pm, starter-kit,
  extension-table and extension-image 3.31.4; vite 7.3.5, vitest 3.2.7,
  happy-dom 20.11.6 and typescript 5.9.3, the admin SPA toolchain
- vite.config.ts builds assets/src/blogeditor/index.ts into fixed-name
  assets/dist/blogeditor.js and blogeditor.css, minified, and runs vitest
  on happy-dom
- scripts/check-dist.sh rebuilds into a temp dir and fails when assets/dist
  is stale; node_modules is ignored

tsconfig.json

@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "strict": true,
+    "noEmit": true,
+    "isolatedModules": true,
+    "skipLibCheck": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true,
+    "types": ["vite/client", "node"]
+  },
+  "include": ["assets/src", "tests", "vite.config.ts"]
+}