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/registry.go

@@ -0,0 +1,59 @@
+package mpd
+
+import (
+	"sort"
+	"strings"
+	"sync"
+)
+
+var (
+	regMu    sync.RWMutex
+	registry = map[string]func() Rewriter{}
+)
+
+func init() {
+	Register("none", func() Rewriter { return Passthrough{} })
+}
+
+// Register makes a rewriter resolvable by name, so consumers (streamd) can pick
+// one from stored config without importing the provider that implements it. A
+// factory is registered rather than an instance because a rewriter may carry
+// per-stream fallback state.
+func Register(name string, newRewriter func() Rewriter) {
+	regMu.Lock()
+	defer regMu.Unlock()
+	registry[strings.ToLower(name)] = newRewriter
+}
+
+// Lookup builds a fresh rewriter for a name. An empty name, "none" or an unknown
+// name yields Passthrough with ok=false, so callers can tell "no rewrite needed"
+// from "rewrite with X".
+func Lookup(name string) (Rewriter, bool) {
+	key := strings.ToLower(strings.TrimSpace(name))
+	if key == "" || key == "none" {
+		return Passthrough{}, false
+	}
+	regMu.RLock()
+	newRewriter, ok := registry[key]
+	regMu.RUnlock()
+	if !ok {
+		return Passthrough{}, false
+	}
+	rw := newRewriter()
+	if _, isPass := rw.(Passthrough); isPass {
+		return rw, false
+	}
+	return rw, true
+}
+
+// Names lists registered rewriter names.
+func Names() []string {
+	regMu.RLock()
+	defer regMu.RUnlock()
+	out := make([]string, 0, len(registry))
+	for k := range registry {
+		out = append(out, k)
+	}
+	sort.Strings(out)
+	return out
+}