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/api.js

@@ -6,9 +6,9 @@
  * Modal processing guard for async form submissions.
  */
 
-import { modelFetch } from './model.js?v=10';
-import { requestUpdate } from './reactivity.js?v=9';
-import { isModalProcessing, setModalProcessing, refreshModals } from './components/modal.js?v=9';
+import { modelFetch } from './model.js';
+import { requestUpdate } from './reactivity.js';
+import { isModalProcessing, setModalProcessing, refreshModals } from './components/modal.js';
 
 /**
  * Global state — shared with auth.js component.