Preserve runner registration evidence

[cbusillo]

Summary

• Preserve runner lane registration workflow artifacts before failing on unexpected executor results.
• Normalize runner host/repository indexed values consistently when storing and filtering registration audit evidence.
• Add store coverage for mixed-case host names so host-scoped audit listings continue to find existing records.

Validation

• uv run python -m unittest tests.test_filesystem_store tests.test_postgres_store
• uv run --extra dev ruff format --check control_plane/storage/filesystem.py control_plane/storage/postgres.py tests/test_filesystem_store.py tests/test_postgres_store.py
• uv run --extra dev ruff check control_plane/storage/filesystem.py control_plane/storage/postgres.py tests/test_filesystem_store.py tests/test_postgres_store.py
• uv run --extra dev mypy control_plane/storage/filesystem.py control_plane/storage/postgres.py tests/test_filesystem_store.py tests/test_postgres_store.py
• actionlint -config-file .github/actionlint.yaml .github/workflows/runner-lane-registration.yml
• git diff --check
• uv run python -m unittest tests.test_runner_lane_registration tests.test_service tests.test_filesystem_store tests.test_postgres_store (602 tests OK)