Implement granular exclusion filters (hidden files, system files)

[djdarcy]

Feature Request

Add more granular control over which files and folders are excluded from timestamp calculations.

Current State

• Basic exclusion through skip_generated flag
• ExclusionFilter class exists but could be enhanced

Proposed Enhancements

1. Hidden Files: Option to exclude files starting with '.'
2. System Files: Enhanced detection of system-generated files
3. Custom Patterns: User-defined glob patterns for exclusion
4. Per-OS Rules: Different rules for Windows vs Unix systems

Example API

filter = ExclusionFilter(
    skip_hidden=True,
    skip_system=True, 
    custom_patterns=['*.tmp', '*.cache'],
    os_specific=True
)

Benefits

• More precise control over what affects folder timestamps
• Better performance by skipping irrelevant files
• Cleaner results for user-facing applications

Related Work

This was identified during the DazzleTreeLib error handling improvements (v0.9.2) but deferred to focus on core functionality.