multistreaming: scenes/composition, installer build support, service updates

- multistreaming (new): RTMP ingest + multi-platform fan-out with pluggable providers (Twitch/YouTube/Kick/custom), zero-knowledge key vaults, Authelia OIDC auth, shared rooms with editor/streamer roles, single-use invites, per-account streaming grants, and scenes & composition (grid/PiP layouts, text/image overlays, per-output audio routing).
- installer: support Dockerfile build in metadata (not just image) and RSA key generation for the Authelia OIDC JWKS.
- authelia: add OIDC provider with portainer + multistreaming clients (public + PKCE).
- services: remove allprox; add nginx-proxy-manager and portainer; update lldap; regenerate catalog.

installer/src/compose.ts

@@ -1,6 +1,11 @@
 import { stringify } from "yaml";
 import type { ServiceMetadata } from "./types.ts";
 
+/** True when the service builds its image from a Dockerfile rather than pulling one. */
+export function usesBuild(meta: ServiceMetadata): boolean {
+  return Boolean(meta.compose && (meta.compose as Record<string, unknown>).build);
+}
+
 /** Build the docker-compose.yml content for a service from its metadata. */
 export function generateComposeFile(meta: ServiceMetadata): string {
   const doc: Record<string, unknown> = {};