fix: Remove forced VP9 codec preference - broke calls in production

Setting video_codec: vp9 resulted in no audio/video being transmitted
in real calls (2026-07-28), despite server-side codec regression
fallback to VP8 appearing to work in LiveKit SFU logs. Root cause not
further isolated beyond this. Leaving video_codec unset (defaults to
vp8) with the same 1440p/60fps/bitrate bump confirmed working.

vite-embedded.config.ts

@@ -31,7 +31,9 @@ export default defineConfig((env) =>
                 delayed_leave_event_delay_ms: 18000,
               },
               media_quality: {
-                video_codec: "vp9",
+                // video_codec intentionally left unset (defaults to vp8) - setting it
+                // to "vp9" broke calls entirely in production (2026-07-28, no audio/video
+                // transmitted). Root cause not confirmed; revisit once isolated.
                 video: {
                   max_resolution: 1440,
                   max_bitrate: 8_000_000,