Remove query-string cache-busting from static assets

Drop ?v=N version pins from all JS imports and HTML <link>/<script> tags.
Cache invalidation is now handled solely by server-side cache-control headers.
Update docs and AGENTS.md accordingly.

webui/static/hoover/component.js

@@ -15,9 +15,9 @@
  *   });
  */
 
-import { reactive } from './reactivity.js?v=9';
-import { h } from './vdom.js?v=9';
-import { _compExpandedCache } from './render.js?v=9';
+import { reactive } from './reactivity.js';
+import { h } from './vdom.js';
+import { _compExpandedCache } from './render.js';
 
 /** Registry of mounted components: key → { state } */
 const _mounted = new Map();