fix: enable Laya language detection and harden live analysis (#18 #19 #20)

Ensure Docker images keep their container-built native dependencies, wait for the Laya sidecar healthcheck, expose accurate Laya readiness, and treat empty AI language batches as fallback failures.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,18 @@
+.git
+.github
+node_modules
+npm-debug.log*
+*.log
+.npm
+.cache
+coverage
+
+# Runtime state must come from volumes or be created inside the image.
+data
+transcode-cache
+
+# Never bake local secrets into an image.
+.env
+.env.*
+!.env.example
+