feat(protocol): freeze M4 native session RC6 contract

fixtures/valid/manifest.json

@@ -25,5 +25,14 @@
     "expires_at": "2099-01-01T00:00:00Z",
     "audience": "versevdi-gateway"
   },
-  "correlation_id": "correlation-1"
+  "correlation_id": "correlation-1",
+  "selected_descriptor": {
+    "video_profile": {"codec": "h264", "bit_depth": 8, "chroma_subsampling": "4:2:0", "color_space": "bt709-limited", "transfer_function": "sdr"},
+    "audio_profile": {"codec": "opus", "sample_rate_hz": 48000, "channels": 2, "channel_layout": "stereo", "packet_duration_ms": 5},
+    "display_mode": {"resolution_width": 1920, "resolution_height": 1080, "fps": 60},
+    "bitrate_target_kbps": 20000,
+    "bitrate_maximum_kbps": 40000,
+    "adjustment": {"display_reason": "none", "bitrate_reason": "none"},
+    "media_timestamp_basis": "gateway-send-wall-clock-ms"
+  }
 }

fixtures/valid/selected-session-descriptor.json

@@ -0,0 +1,9 @@
+{
+  "video_profile": {"codec": "hevc", "bit_depth": 8, "chroma_subsampling": "4:2:0", "color_space": "bt709-limited", "transfer_function": "sdr"},
+  "audio_profile": {"codec": "opus", "sample_rate_hz": 48000, "channels": 2, "channel_layout": "stereo", "packet_duration_ms": 5},
+  "display_mode": {"resolution_width": 2560, "resolution_height": 1440, "fps": 120},
+  "bitrate_target_kbps": 40000,
+  "bitrate_maximum_kbps": 50000,
+  "adjustment": {"display_reason": "none", "bitrate_reason": "policy_default"},
+  "media_timestamp_basis": "gateway-send-wall-clock-ms"
+}

fixtures/valid/session-quality-limits.json

@@ -0,0 +1,9 @@
+{
+  "policy_version_id": "policy-1",
+  "policy_display_limit": {"resolution_width": 3840, "resolution_height": 2160, "fps": 120},
+  "selectable_display_maximum": {"resolution_width": 3840, "resolution_height": 2160, "fps": 120},
+  "display_limit_override": false,
+  "bitrate_minimum_kbps": 1000,
+  "bitrate_target_kbps": 20000,
+  "bitrate_maximum_kbps": 50000
+}

fixtures/valid/session-request.json

@@ -2,5 +2,9 @@
   "client_device_id": "device-1",
   "device_key_id": "key-1",
   "pool_id": "pool-1",
-  "idempotency_key": "request-1"
+  "idempotency_key": "request-1",
+  "video_profiles": [
+    {"codec": "h264", "bit_depth": 8, "chroma_subsampling": "4:2:0", "color_space": "bt709-limited", "transfer_function": "sdr"}
+  ],
+  "bitrate_preference": {"mode": "auto"}
 }