Summary - validate snap names during init name resolution so directory-derived names can fall back to the default - keep explicit invalid names failing with Snapcraft's snap name validation - add coverage for long working directory names Issue Closes #6093 Validation - pytest -q tests/unit/services/test_init.py tests/unit/commands/test_init.py -rs - ruff check snapcraft/services/init.py tests/unit/services/test_init.py tests/unit/commands/test_init.py - ruff format snapcraft/services/init.py tests/unit/services/test_init.py tests/unit/commands/test_init.py - git diff --check