feat: add Zephyr RTOS .gitignore template by srpatcha · Pull Request #4852 · github/gitignore

Add gitignore template for Zephyr RTOS projects covering:
- Build artifacts and twister output
- Generated config/devicetree files
- West workspace metadata
- Python virtual environments

Add a comprehensive template validation tool that checks for:
- Valid glob pattern syntax
- Duplicate pattern detection
- Conflicting include/exclude rules
- Coverage analysis with suggestions
- CLI interface with argparse
- Detailed reporting (errors, warnings, suggestions)
- Support for processing all templates in the repo

Signed-off-by: Srikanth Patchava <spatchava@meta.com>

Trailing whitespace in .gitignore patterns can cause unexpected
behavior. This script detects and removes trailing whitespace
from template files with dry-run support.

Signed-off-by: Srikanth Patchava <spatchava@meta.com>

Comprehensive test suite covering glob validation, trailing
whitespace detection, duplicate and conflict detection,
coverage analysis, and report formatting.

Signed-off-by: Srikanth Patchava <spatchava@meta.com>