lotus(#1): make denoise asset base absolute (fixes DTLN/DFN load)

Review found native dynamic import() of the DTLN/DeepFilterNet ESM
resolves "./denoise/…" against the bundled JS chunk's URL (-> /assets/…)
not the document, so those two models 404'd and silently fell back to raw
mic in the default config. Resolve the asset base to an absolute
same-origin href against the document; addModule()/fetch() accept absolute
too, so all three load paths stay consistent. (rnnoise/speex were
unaffected since addModule resolves against the document.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lotus/lotusDenoise.ts

@@ -39,7 +39,12 @@ import {
  * malformed value falls back to the bundled "./denoise/".
  */
 function safeAssetBase(raw: string | null): string {
-  const fallback = "./denoise/";
+  // Resolve to an ABSOLUTE same-origin href against the document. Absolute is
+  // required because native dynamic `import()` (DTLN/DeepFilterNet) resolves a
+  // relative specifier against the JS chunk's URL, not the document — so a
+  // relative "./denoise/" would 404. addModule()/fetch() work with absolute
+  // too, so this keeps all three asset-load paths consistent.
+  const fallback = new URL("./denoise/", window.location.href).href;
   if (!raw) return fallback;
   try {
     const u = new URL(raw, window.location.href);