feat(video+desktop): camera capture, video UI, E2E AEAD wiring, test fixes

Blockers 4 & 5: browser getUserMedia → JPEG IPC → Rust I420 pipeline;
remote video strip renders decoded frames via canvas; EncryptingTransport
wraps QuinnTransport so WZP AEAD is applied to all media (C2 fix).

Test fixes: HandshakeResult.session destructuring across relay/client/crypto
integration tests; video_codecs field added to all CallOffer/CallAnswer
structs; wzp-video pipeline_roundtrip integration tests added.

PRD docs: five Kimi-ready specs for E2E encryption, Android NDK 0.9 migration,
quality upgrade flow, wire-format hardening, and clippy debt.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/wzp-codec/src/denoise.rs

@@ -56,7 +56,7 @@ impl NoiseSupressor {
 
             // f32 → i16 with clamping
             for (i, &val) in output.iter().enumerate() {
-                let clamped = val.max(-32768.0).min(32767.0);
+                let clamped = val.clamp(-32768.0, 32767.0);
                 pcm[offset + i] = clamped as i16;
             }
         }