Include/Exclude glob patterns for diff scanning

[LeeSinLiang]

Include/Exclude glob patterns for diff scanning

Summary
Add include / exclude glob arrays in .commitlm-config.json to filter which files influence commit message & doc generation.

Motivation
Ignoring docs/**, lockfiles, binaries, or vendor folders reduces token usage and noise.

Proposed config shape

{
  "include": ["src/**", "app/**"],
  "exclude": ["docs/**", "**/*.lock", "**/*.min.*", "node_modules/**", "*.png", "*.jpg"]
}

Scope

• Apply patterns to both commit message and documentation generation paths.
• Precedence: evaluate include first, then apply exclude.
• Cross-platform support (Windows path separators).

Tasks

• Parse arrays from config; implement precedence.
• Use robust matching (e.g., pathspec or fnmatch) with repository root context.
• Unit tests for common patterns and nested repos.
• README section with examples.

Acceptance criteria

• Files matching exclude never influence prompts.
• Patterns work on Linux/macOS/Windows.
• Tests cover at least 6 representative patterns.

Test plan
Create a temp repo with mixed files; assert only expected files feed the generator.