Add type annotations to resolve ty type checker issues

[Copilot]

The ty type checker flagged 20 type errors in the codebase, primarily in CleanupRunner class attributes and usage patterns.

Changes

pyclean/runner.py

• Added type annotations to CleanupRunner attributes: Callable[[Path], None] for methods, list[str] for ignore patterns, int for counters
• Annotated configure(args: argparse.Namespace) -> None parameter
• Initialized callable attributes with placeholder functions instead of None to eliminate union types

pyclean/traversal.py

• Updated should_ignore() signature to accept list[str] | None for ignore_patterns, matching runtime behavior where None is handled via early return

tests/test_traversal.py

• Fixed test calls to should_ignore() to pass str instead of Path objects

Before/After

# Before: ty complained about None unions
class CleanupRunner:
    def __init__(self):
        self.unlink = None  # Type: None, but later assigned callable
        self.ignore = None  # Type: None, but later assigned list
        
# After: explicit types, no unions
class CleanupRunner:
    def __init__(self):
        self.unlink: Callable[[Path], None] = _noop_file
        self.ignore: list[str] = []

All 20 type errors resolved. Type checking now passes cleanly with ty check.

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