**chore(docs):** add .gitignore for docs and introduce bun.lock file

- Add `.gitignore` to exclude `node_modules/`, `.vitepress/cache/`, and `.vitepress/dist/` directories
- Include `bun.lock` for dependency management with Bun

.claude/CLAUDE.md

@@ -27,6 +27,11 @@ docker compose -f compose.dev.yml up -d
 bun install          # install deps
 bun run dev          # dev server on :5173 (proxies /api and /webhook to :8080)
 bun run build        # production build → frontend/dist/
+
+# Documentation site (from docs/ directory)
+bun install          # install deps
+bun run dev          # VitePress dev server on :5174
+bun run build        # production build → docs/.vitepress/dist/
 ```
 
 CI warns (but does not fail) when coverage drops below 80%.
@@ -41,6 +46,8 @@ The app is a Go HTTP server that receives [DIUN](https://crazymax.dev/diun/) web
 - `pkg/diunwebhook/diunwebhook_test.go` — external test package (`package diunwebhook_test`); uses `httptest` for handler tests
 - `pkg/diunwebhook/export_test.go` — test-only exports
 - `frontend/` — React SPA (Bun + Vite + React 19 + Tailwind CSS + shadcn/ui + dnd-kit)
+- `docs/` — VitePress documentation site
+- `CONTRIBUTING.md` — developer guide (project structure, development setup, testing, CI/CD)
 
 **Database schema (SQLite):**
 - `updates` — one row per image (PRIMARY KEY `image`), stores full event fields plus `received_at` and `acknowledged_at`