[ci skip] Add reverse proxy mode to f1-stream

Replace CPU-intensive headless Chrome + WebRTC pipeline with a
lightweight Go reverse proxy that strips anti-framing headers
(X-Frame-Options, CSP) and embeds streaming sites in iframes.

- New internal/proxy package with URL rewriting for HTML/CSS
- JS shim injection to intercept fetch/XHR/WebSocket/createElement
- Referer reconstruction for correct cross-origin auth (HLS streams)
- Inline iframe viewer preserving site navigation (not fullscreen overlay)

modules/kubernetes/f1-stream/files/static/js/utils.js

@@ -0,0 +1,9 @@
+function escapeHtml(str) {
+  const div = document.createElement('div');
+  div.textContent = str;
+  return div.innerHTML;
+}
+
+function escapeAttr(str) {
+  return str.replace(/&/g, '&amp;').replace(/'/g, '&#39;').replace(/"/g, '&quot;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
+}