chore: remove unnecessary debug logging

Frontend:
- Remove 4 console.log statements from terminal.tsx that flooded the
  browser console with WebSocket traffic (open, received X bytes, sending Y,
  xterm focused)

Backend:
- Downgrade Dockerfile/entrypoint compilation logs from INFO to DEBUG in
  _prepare_manifest_instance
- Remove hex-dump diagnostic logging from docker_build.py (was for
  troubleshooting the backslash continuation bug, now fixed)
- Downgrade Dockerfile write log from INFO to DEBUG

apps/api/src/services/docker_build.py

@@ -31,13 +31,7 @@ def build_image(
     # Write Dockerfile
     dockerfile_path = Path(instance_dir) / "Dockerfile"
     dockerfile_path.write_text(dockerfile, newline="\n")
-    logger.info("Wrote Dockerfile to %s (%d bytes)", dockerfile_path, len(dockerfile))
-    logger.debug("Dockerfile content:\n%s", dockerfile)
-
-    # Hex-dump first 8 lines so we can see exactly what bytes Docker receives
-    lines_for_hex = dockerfile.split("\n")[:8]
-    for i, line in enumerate(lines_for_hex, start=1):
-        logger.info("Dockerfile line %d hex: %s", i, line.encode("utf-8").hex())
+    logger.debug("Wrote Dockerfile to %s (%d bytes)", dockerfile_path, len(dockerfile))
 
     # Write build context files
     if build_context: