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>

desktop/src-tauri/Cargo.toml

@@ -44,6 +44,9 @@ tracing = "0.1"
 tracing-subscriber = "0.3"
 anyhow = "1"
 rustls = { version = "0.23", default-features = false, features = ["ring", "std"] }
+# JPEG encoding for video:frame events (I420 → RGB → JPEG for IPC to WebView)
+image = { version = "0.25", default-features = false, features = ["jpeg"] }
+base64 = "0.22"
 
 # WarzonePhone crates — protocol layer is platform-independent
 wzp-proto = { path = "../../crates/wzp-proto" }
@@ -51,6 +54,7 @@ wzp-codec = { path = "../../crates/wzp-codec" }
 wzp-fec = { path = "../../crates/wzp-fec" }
 wzp-crypto = { path = "../../crates/wzp-crypto" }
 wzp-transport = { path = "../../crates/wzp-transport" }
+wzp-video = { path = "../../crates/wzp-video" }
 
 # wzp-client pulls in CPAL on every desktop target and, additionally on
 # macOS, VoiceProcessingIO (coreaudio-rs behind the "vpio" feature). The
@@ -99,6 +103,10 @@ libloading = "0.8"
 jni = "0.21"
 ndk-context = "0.1"
 
+[dev-dependencies]
+bytes = "1"
+async-trait = "0.1"
+
 [features]
 default = ["custom-protocol"]
 custom-protocol = ["tauri/custom-protocol"]