Initial commit: Null DRM Official

Capture, decrypt, and restream toolkit with compiled-in app modules
(RTE, TG4, BBC), on-device MITM proxy, streamd control plane, and www.
BBC module.yaml is published (clear streams); other module values stay local.

apps/pkg/mpd/mpd.go

@@ -0,0 +1,15 @@
+package mpd
+
+// Rewriter transforms an upstream live MPD into something N_m3u8DL-RE can
+// refresh safely. Apps that need DAI/colon stripping or synthetic timelines
+// implement this; others return Passthrough.
+type Rewriter interface {
+	Name() string
+	Rewrite(upstreamXML []byte, kidHint string) (out []byte, err error)
+}
+
+// Passthrough leaves the MPD unchanged.
+type Passthrough struct{}
+
+func (Passthrough) Name() string { return "none" }
+func (Passthrough) Rewrite(in []byte, _ string) ([]byte, error) { return in, nil }