chore(tests): remove orphaned v1 tests for removed /api/projects endpoint (#667)

test_project_creation_api.py (cf-11) and test_workspace_cleanup.py (Issue #7)
exercise the v1 POST /api/projects route removed in 66241c2 (remove orphaned v1
web layer). No v2 marker, so CI's -m v2 suite never ran them; they 404 on a full
local run. Dead weight. v2-equivalent coverage lives in tests/ui. Kept
tests/cli/test_api_client.py (mocked CLI client helper, still passes).

Author: frankbria