Covers each new code path that the design's §6 table requires:
- Subscribe -> 406 on non-H264 / non-Opus offer (TestHandler_Subscribe_406OnCodecMismatch)
- Subscribe -> 503 when total cap exhausted (TestHandler_Subscribe_503OnTotalCap)
- Subscribe -> 503 when per-stream cap exhausted (TestHandler_Subscribe_503OnPerStreamCap)
- Trickle -> 404 on unknown resource (TestHandler_Trickle_404WhenUnknown)
- preflight -> 204 + CORS headers (TestHandler_PreflightCORS)
- Register installs all 5 routes (TestHandler_RegisterMountsAllRoutes)
- Close drains the index without panicking (TestHandler_Close_DrainsPeers)
- requireH264AndOpus table-driven (TestRequireH264AndOpus)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
