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/source-map-js/source-map.js

@@ -0,0 +1,8 @@
+/*
+ * Copyright 2009-2011 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE.txt or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+exports.SourceMapGenerator = require('./lib/source-map-generator').SourceMapGenerator;
+exports.SourceMapConsumer = require('./lib/source-map-consumer').SourceMapConsumer;
+exports.SourceNode = require('./lib/source-node').SourceNode;