fix(http/api): carry process WebRTC config through the API DTO

ProcessConfig in http/api/process.go shipped without a WebRTC field, so
JSON arriving at POST /api/v3/process was silently stripped of
"webrtc":{"enabled":true}. Marshal() handed restream a zero
ConfigWebRTC, the OnProcessStart hook no-op'd, and every WHEP request
returned 404 — even with a running webrtc-enabled process.

Caught on the M2 TrueNAS deploy at acceptance time: GET /process/{id}/config
came back without the webrtc block, despite the inbound JSON having it.
This is the API-layer twin of the earlier 'fix(config): preserve WebRTC
section in Config.Clone()' — same class of bug (drop-on-copy), different
struct.

- Add ProcessConfigWebRTC mirroring app.ConfigWebRTC.
- Marshal: copy DTO -> app.Config.WebRTC.
- Unmarshal: copy app.Config.WebRTC -> DTO.
- Regression tests cover both the JSON->DTO->Config path and the
  default (no webrtc block) case.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

http/api/process.go

@@ -43,18 +43,26 @@ type ProcessConfigLimits struct {
 }
 
 // ProcessConfig represents the configuration of an ffmpeg process
+type ProcessConfigWebRTC struct {
+	Enabled        bool  `json:"enabled"`
+	VideoPT        uint8 `json:"video_pt,omitempty"`
+	AudioPT        uint8 `json:"audio_pt,omitempty"`
+	ForceTranscode bool  `json:"force_transcode,omitempty"`
+}
+
 type ProcessConfig struct {
-	ID             string              `json:"id"`
-	Type           string              `json:"type" validate:"oneof='ffmpeg' ''" jsonschema:"enum=ffmpeg,enum="`
-	Reference      string              `json:"reference"`
-	Input          []ProcessConfigIO   `json:"input" validate:"required"`
-	Output         []ProcessConfigIO   `json:"output" validate:"required"`
-	Options        []string            `json:"options"`
-	Reconnect      bool                `json:"reconnect"`
-	ReconnectDelay uint64              `json:"reconnect_delay_seconds" format:"uint64"`
-	Autostart      bool                `json:"autostart"`
-	StaleTimeout   uint64              `json:"stale_timeout_seconds" format:"uint64"`
-	Limits         ProcessConfigLimits `json:"limits"`
+	ID             string               `json:"id"`
+	Type           string               `json:"type" validate:"oneof='ffmpeg' ''" jsonschema:"enum=ffmpeg,enum="`
+	Reference      string               `json:"reference"`
+	Input          []ProcessConfigIO    `json:"input" validate:"required"`
+	Output         []ProcessConfigIO    `json:"output" validate:"required"`
+	Options        []string             `json:"options"`
+	Reconnect      bool                 `json:"reconnect"`
+	ReconnectDelay uint64               `json:"reconnect_delay_seconds" format:"uint64"`
+	Autostart      bool                 `json:"autostart"`
+	StaleTimeout   uint64               `json:"stale_timeout_seconds" format:"uint64"`
+	Limits         ProcessConfigLimits  `json:"limits"`
+	WebRTC         ProcessConfigWebRTC  `json:"webrtc"`
 }
 
 // Marshal converts a process config in API representation to a restreamer process config
@@ -70,6 +78,12 @@ func (cfg *ProcessConfig) Marshal() *app.Config {
 		LimitCPU:       cfg.Limits.CPU,
 		LimitMemory:    cfg.Limits.Memory * 1024 * 1024,
 		LimitWaitFor:   cfg.Limits.WaitFor,
+		WebRTC: app.ConfigWebRTC{
+			Enabled:        cfg.WebRTC.Enabled,
+			VideoPT:        cfg.WebRTC.VideoPT,
+			AudioPT:        cfg.WebRTC.AudioPT,
+			ForceTranscode: cfg.WebRTC.ForceTranscode,
+		},
 	}
 
 	cfg.generateInputOutputIDs(cfg.Input)
@@ -150,6 +164,11 @@ func (cfg *ProcessConfig) Unmarshal(c *app.Config) {
 	cfg.Limits.Memory = c.LimitMemory / 1024 / 1024
 	cfg.Limits.WaitFor = c.LimitWaitFor
 
+	cfg.WebRTC.Enabled = c.WebRTC.Enabled
+	cfg.WebRTC.VideoPT = c.WebRTC.VideoPT
+	cfg.WebRTC.AudioPT = c.WebRTC.AudioPT
+	cfg.WebRTC.ForceTranscode = c.WebRTC.ForceTranscode
+
 	cfg.Options = make([]string, len(c.Options))
 	copy(cfg.Options, c.Options)
 

http/api/process_webrtc_test.go

@@ -0,0 +1,81 @@
+package api
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/datarhei/core/v16/restream/app"
+)
+
+// TestProcessConfigWebRTCRoundtrip locks down the API DTO ↔ restream
+// app.Config mapping for the per-process WebRTC block.
+//
+// Regression: the M2 cut shipped without WebRTC on ProcessConfig, so
+// JSON arriving at POST /api/v3/process was silently stripped of
+// `webrtc.enabled`, the restream config never saw it, the start hook
+// never bound a Source, and WHEP returned 404. This test fails on the
+// pre-fix code (Marshal would yield `app.ConfigWebRTC{}`) and passes
+// once the DTO carries the field.
+func TestProcessConfigWebRTCRoundtrip(t *testing.T) {
+	// 1. JSON in → DTO → app.Config
+	body := []byte(`{
+	  "id":"p","input":[{"id":"i","address":"x"}],"output":[{"id":"o","address":"-"}],
+	  "webrtc":{"enabled":true,"video_pt":102,"audio_pt":111,"force_transcode":true}
+	}`)
+	var dto ProcessConfig
+	if err := json.Unmarshal(body, &dto); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if !dto.WebRTC.Enabled {
+		t.Fatalf("DTO.WebRTC.Enabled lost on JSON decode: %+v", dto.WebRTC)
+	}
+	cfg := dto.Marshal()
+	if !cfg.WebRTC.Enabled || cfg.WebRTC.VideoPT != 102 || cfg.WebRTC.AudioPT != 111 || !cfg.WebRTC.ForceTranscode {
+		t.Fatalf("app.Config.WebRTC mapped wrong: %+v", cfg.WebRTC)
+	}
+
+	// 2. app.Config → DTO → JSON out
+	stored := &app.Config{
+		ID:    "p",
+		Input: []app.ConfigIO{{ID: "i", Address: "x"}},
+		Output: []app.ConfigIO{{ID: "o", Address: "-"}},
+		WebRTC: app.ConfigWebRTC{
+			Enabled:        true,
+			VideoPT:        102,
+			AudioPT:        111,
+			ForceTranscode: true,
+		},
+	}
+	var dto2 ProcessConfig
+	dto2.Unmarshal(stored)
+	if !dto2.WebRTC.Enabled || dto2.WebRTC.VideoPT != 102 {
+		t.Fatalf("Unmarshal lost WebRTC: %+v", dto2.WebRTC)
+	}
+	out, err := json.Marshal(dto2)
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	// Decode again and compare.
+	var dto3 ProcessConfig
+	if err := json.Unmarshal(out, &dto3); err != nil {
+		t.Fatalf("re-unmarshal: %v", err)
+	}
+	if dto3.WebRTC != dto.WebRTC {
+		t.Fatalf("roundtrip diverged: in=%+v out=%+v", dto.WebRTC, dto3.WebRTC)
+	}
+}
+
+// TestProcessConfigWebRTCDefaults: when "webrtc" is absent in the
+// inbound JSON, Marshal must still produce a valid app.Config — the
+// zero ConfigWebRTC means "disabled" and the start hook should no-op.
+func TestProcessConfigWebRTCDefaults(t *testing.T) {
+	body := []byte(`{"id":"p","input":[{"id":"i","address":"x"}],"output":[{"id":"o","address":"-"}]}`)
+	var dto ProcessConfig
+	if err := json.Unmarshal(body, &dto); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	cfg := dto.Marshal()
+	if cfg.WebRTC.Enabled {
+		t.Fatalf("default should be disabled, got %+v", cfg.WebRTC)
+	}
+}