Merge branch 'backend-refactor-rev' into audit-merge-three

Adapt the refactored web player to the new backend API (id path params,
bulk track adds, flat list items, mix kind) and port AddAlbumToPlayList
to the backend conventions.

deploy/compose.yml

@@ -321,7 +321,6 @@ services:
       ASPNETCORE_URLS: http://+:5111
       StreamGateway__PublicBaseUrl: ${PUBLIC_STREAM_URL}
       StreamTicket__PrivateKeyPath: /keys/stream_private.pem
-      Workers__Routes__TemporaryFilesDirectory: /tmp/musify
       # AUTH_CLIENT_ID is written to the env file by the zitadel-init service.
       Authentication__MetadataAddress: "${PUBLIC_AUTH_URL}/.well-known/openid-configuration"
       Authentication__IssuerAddress: ${PUBLIC_AUTH_URL}
@@ -347,11 +346,18 @@ services:
     depends_on:
       migrate:
         condition: service_completed_successfully
+      keys-init:
+        condition: service_completed_successfully
     environment:
       <<: *backend-env
       DOTNET_ENVIRONMENT: ${DOTNET_ENVIRONMENT}
-      AudioTranscoder__Routes__WorkingDirectory: /tmp/musify
+      # The Application handlers need these to build their dependencies; the
+      # Worker never issues stream tickets, so the key is never read.
+      StreamGateway__PublicBaseUrl: ${PUBLIC_STREAM_URL}
+      StreamTicket__PrivateKeyPath: /keys/stream_private.pem
       Workers__Routes__TemporaryFilesDirectory: /tmp/musify
+    volumes:
+      - ./keys:/keys:ro
     restart: unless-stopped
 
   # YARP in front of the SeaweedFS filer: validates the RS256 stream ticket and