Separate JSON API backend (vm_api.py) + React+TanStack frontend scaffold

- vm_api.py: pure FastAPI JSON API on :8098 with CORS
- vm-api.service: systemd unit for API (replaces inline HTML vm_web.py for frontend)
- vm_web.py: kept intact as fallback; Apache now proxies /api/ -> :8098
- frontend/: Vite + React + TanStack Query scaffold
- Apache vhost updated: DocumentRoot -> frontend/dist, /api/ proxy, SPA fallback
- All original HTML pages still functional via :8099 during transition

frontend/node_modules/update-browserslist-db/README.md

@@ -0,0 +1,41 @@
+# Update Browserslist DB
+
+<img width="120" height="120" alt="Browserslist logo by Anton Popov"
+     src="https://browsersl.ist/logo.svg" align="right">
+
+CLI tool to update `caniuse-lite` with browsers DB
+from [Browserslist](https://github.com/browserslist/browserslist/) config.
+
+Some queries like `last 2 versions` or `>1%` depend on actual data
+from `caniuse-lite`.
+
+```sh
+npx update-browserslist-db@latest
+```
+
+Or if using `pnpm`:
+
+```sh
+pnpm dlx update-browserslist-db latest
+```
+
+Or if using `bun`:
+
+```sh
+bunx update-browserslist-db@latest
+```
+
+Or if using `yarn` 2+:
+
+```sh
+yarn dlx update-browserslist-db@latest
+```
+
+---
+
+<img src="https://cdn.evilmartians.com/badges/logo-no-label.svg" alt="" width="22" height="16" />  Update Browserslist DB is built by <b><a href="https://evilmartians.com/">Evil Martians</a></b>, an American design and engineering consultancy for <b>developer tools, AI, and cybersecurity startups</b>.
+
+---
+
+## Docs
+Read full docs **[here](https://github.com/browserslist/update-db#readme)**.