Fix Docker image bloat: exclude local venvs from build context, move transformers.js to devDependencies.

.dockerignore

@@ -15,6 +15,17 @@ docker-compose.yml
 __pycache__/
 *.pyc
 
+# Local Python virtualenvs for developing/testing the sidecar against a real
+# faster-whisper install (e.g. server-py/venv, server-py/.venv). A nested
+# venv/.gitignore keeps these out of `git status`, but Docker does not read
+# .gitignore, so without this they silently ride along in `COPY server-py
+# ./server-py` — confirmed to balloon the "Bun-only" image from the documented
+# ~244 MB to 2.18 GB and bake a machine-specific interpreter path nothing in
+# the container would ever use (the with-server-engine target builds its own
+# venv from requirements.txt at /opt/faster-whisper).
+**/venv/
+**/.venv/
+
 # Editor / agent state
 .idea
 .claude