T4.1: wzp-video crate scaffold + H.264 NAL framer + depacketizer

crates/wzp-client/src/call.rs

@@ -654,6 +654,9 @@ impl CallDecoder {
             },
             CodecId::Codec2_1200 => QualityProfile::CATASTROPHIC,
             CodecId::ComfortNoise => QualityProfile::GOOD,
+            CodecId::H264Baseline => {
+                panic!("H264Baseline is a video codec; audio decoder called with video profile")
+            }
         }
     }