fix(makefile): sync parakeet-onnx extra in .installed before asset validation
Whenever pyproject.toml or uv.lock change, .installed is invalidated
and re-runs `uv sync`, which prunes the parakeet-onnx-cpu/cuda extras
that `make install` had previously synced. The asset-hash validation
that follows then fails to import `observe.transcribe.main` because
onnxruntime is missing.
Add the same `uv sync --extra parakeet-onnx-$(PARAKEET_ONNX_VARIANT)`
call (Linux x86_64 only) to .installed, before the validation step,
mirroring the existing block in the `install` target.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>