Deploy tab endpoints (merge, GGUF export, GitHub push) not covered by integration tests

[SahilKumar75]

Context

The 7-step wizard's Deploy tab (step 7) calls several API endpoints that were added in the recent wizard implementation. These endpoints exist in app/api.py but have no test coverage in tests/.

Uncovered endpoints

Endpoint	Method	Purpose
/api/jobs/{id}/merge	POST	Merge adapter into base model
/api/jobs/{id}/export-gguf	GET	Convert merged model to GGUF
/api/jobs/{id}/push-github	POST	Push adapter to GitHub repo
/api/jobs/{id}/push-hub	POST	Push adapter to HF Hub
/api/jobs/{id}/commentary	GET	Generate training summary commentary
/api/jobs/{id}/eval	POST	Run evaluation on fine-tuned model
/api/jobs/{id}/infer	POST	Run inference for test-chat

Tasks

• Add integration tests for each endpoint in tests/test_api.py
• Mock Celery tasks and file-system calls as done in existing tests
• Cover both success (200) and error (404 job not found, 500 task failure) paths
• Ensure no real model downloads occur in CI (use pytest-mock / unittest.mock)

Reference

Existing patterns in tests/test_api.py and tests/test_workers.py.