Flaky test: test_cli_apply_duplicated_featureview_names fails with empty output on subprocess timeout

Summary

test_cli_apply_duplicated_featureview_names is intermittently failing in CI (observed on parallel pytest-xdist workers):

FAILED sdk/python/tests/unit/cli/test_cli_apply_duplicates.py::test_cli_apply_duplicated_featureview_names
  AssertionError: assert (-1 != 0 and b'Feature view names must be case-insensitively unique' in b'')

The return code -1 and empty output b'' indicate the subprocess timed out and was killed before producing any output.

Root Cause

Duplicate feature view name detection happens too late in the pipeline — inside store.plan() / store.apply() via _validate_feature_views() in feature_store.py. By that point, FeatureStore and its dependencies (Dask, registry, provider) have already been initialized.

The call chain is:

1. CLI apply_total_command calls apply_total(), which calls _get_repo_contents() (parses repo), then _get_store_and_registry() (creates FeatureStore), then apply_total_with_repo_instance(), then store.plan(), then _validate_all_feature_views(), which finally raises ConflictingFeatureViewNames.
2. The CLI only catches FeastProviderLoginError, so ConflictingFeatureViewNames propagates as an unhandled exception (raw traceback).
3. During process shutdown, slow atexit handlers (Dask thread pool, PySpark JVM) can block indefinitely.
4. The test helper CliRunner.run_with_output() has a 60s timeout — when exceeded, it sends SIGKILL and the output is lost.

This creates two compounding problems:

• The error is raised too late — after heavy initialization that can trigger slow cleanup on exit
• The CLI does not handle the error — producing a traceback instead of a clean message, and not exiting promptly

Proposed Fix

1. Detect duplicate names at parse time in parse_repo() (repo_operations.py): Track feature view names (across FeatureView, BatchFeatureView, StreamFeatureView, OnDemandFeatureView) and data source names during collection. Raise ConflictingFeatureViewNames / DataSourceRepeatNamesException immediately when a collision is found — before FeatureStore or any heavy dependencies are initialized.

2. Catch FeastError in CLI plan/apply commands (cli/cli.py): Add except FeastError handlers (after the existing FeastProviderLoginError handler) to print a clean error message and exit with code 1, instead of letting validation errors propagate as unhandled tracebacks.

Environment

• Observed on macOS CI runners with pytest-xdist parallel execution ([gw2])
• Python 3.11.9

Affected Tests

• test_cli_apply_duplicated_featureview_names
• test_cli_apply_duplicate_data_source_names (same pattern, same risk)
• test_cli_apply_duplicated_featureview_names_multiple_py_files (same pattern, same risk)