Enforce unique hook names and keyword-only validators

[nyxst4ck]

Summary

• report the yamlfix pre-commit hook with its own name instead of pyproject-fmt
• make the two remaining query validators keyword-only, matching the rest of the validator/runner APIs
• add custom linter regressions so duplicate hook IDs/names and positional validate_*/run_* parameters cannot recur

Reproduction

Before the fix, the focused custom-linter tests fail with:

• Pre-commit hook names must be unique because pyproject-fmt is used twice
• Functions must be keyword-only listing validate_accept_header and validate_auth_header_has_signature

Both existing call sites already pass request_headers by keyword, so the signature correction does not require call-site changes.

Tests

• uv run pytest ci/test_custom_linters.py -q -k 'pre_commit_hook_identifiers_unique or validate_and_run_functions_are_keyword_only' ? 2 passed
• uv run ruff check ci/test_custom_linters.py src/mock_vws/_query_validators/accept_header_validators.py src/mock_vws/_query_validators/auth_validators.py ? passed
• uv run ruff format --check ci/test_custom_linters.py src/mock_vws/_query_validators/accept_header_validators.py src/mock_vws/_query_validators/auth_validators.py ? passed

Fixes #3401