[WIP] Add function to scan buffer for conflicts

[Copilot]

• Explore repository structure and understand existing code patterns
• Create new conflict scanning module (lua/maplayer/conflict.lua)
• Implement git availability check
• Implement async git conflict detection using vim.system
• Implement fallback line-by-line scanning for when git is not available
• Add configuration for conflict markers
• Test the implementation with sample conflict files
• Verify async behavior and performance improvements
• Run linters and ensure code quality
• Request code review

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.