chore: add commit guidelines and git configuration

Add Conventional Commits enforcement:
- commit-msg hook validates format automatically
- COMMIT_GUIDELINES.md documents standards
- DEVELOPMENT.md provides best practices

Consolidate author identity:
- .mailmap unifies b0ony/codenimja to single identity
- Set local git config to codenimja for consistency

Update CONTRIBUTING.md:
- Add commit message format section
- Document type/scope conventions
- Provide examples for contributors

Addresses commit consistency going forward without rewriting history.

Author: codenimja

.github/COMMIT_GUIDELINES.md

@@ -0,0 +1,43 @@
+# Git Hooks
+
+This directory contains git hooks for maintaining code quality and consistency.
+
+## commit-msg
+
+Validates commit messages follow Conventional Commits format.
+
+Format: `type(scope): description`
+
+Allowed types:
+- feat: New feature
+- fix: Bug fix
+- docs: Documentation changes
+- chore: Maintenance tasks
+- refactor: Code restructuring
+- test: Test additions/changes
+- perf: Performance improvements
+- ci: CI/CD changes
+- revert: Revert previous commit
+- style: Code style changes
+- build: Build system changes
+
+Examples:
+- `feat(channels): add MPSC support`
+- `fix(async): correct polling timeout`
+- `docs: update README performance numbers`
+
+## Installation
+
+Hooks are automatically active when you clone the repository. If you need to reinstall:
+
+```bash
+chmod +x .git/hooks/commit-msg
+```
+
+## Bypassing Hooks
+
+Not recommended, but possible with:
+
+```bash
+git commit --no-verify -m "your message"
+```

.github/DEVELOPMENT.md

@@ -0,0 +1,85 @@
+# Development Guidelines
+
+## Commit Best Practices
+
+### Size Guidelines
+
+Keep commits focused and atomic:
+
+**Good commit sizes:**
+- Single feature or fix
+- Related changes only
+- Under 500 lines changed (guideline, not hard limit)
+- One logical unit of work
+
+**Avoid:**
+- Mixing unrelated changes
+- Large initial dumps (split into logical commits)
+- Multiple features in one commit
+- Documentation + code changes (separate when possible)
+
+### When to Split Commits
+
+If your commit includes multiple of these, consider splitting:
+- Feature implementation
+- Test additions
+- Documentation updates
+- Refactoring
+- Bug fixes
+
+### Example Split Strategy
+
+Instead of:
+```
+feat: add MPSC with tests and docs (1000+ lines)
+```
+
+Do:
+```
+feat(channels): implement MPSC core algorithm
+test(channels): add MPSC unit tests
+test(performance): add MPSC benchmark suite
+docs: update README for MPSC support
+```
+
+## Revert Strategy
+
+### When to Revert
+
+Use `git revert` for:
+- Published commits (already pushed)
+- Tagged releases
+- Shared branches
+
+### When to Amend/Reset
+
+Use `git commit --amend` or `git reset` for:
+- Local commits only (not pushed)
+- Work-in-progress branches
+- Before creating PR
+
+### Best Practice
+
+Before pushing:
+```bash
+# Review your changes
+git log --oneline -5
+git diff origin/main
+
+# Amend if needed (local only)
+git commit --amend
+
+# Once pushed, use revert
+git revert <commit-hash>
+```
+
+## Code Review Checklist
+
+Before submitting PR:
+- [ ] Commits follow Conventional Commits format
+- [ ] Each commit is focused and atomic
+- [ ] Tests pass locally
+- [ ] Benchmarks run without regression
+- [ ] Documentation updated
+- [ ] No debug code or commented blocks
+- [ ] Author email consistent (codenimja)

.mailmap

@@ -0,0 +1,5 @@
+# .mailmap - Consolidate author identities
+
+# Consolidate different names/emails to single identity
+codenimja <byronpredicts@gmail.com> b0ony <byronpredicts@gmail.com>
+codenimja <byronpredicts@gmail.com> boonzy <byronpredicts@gmail.com>

docs/CONTRIBUTING.md

@@ -90,6 +90,54 @@ nimble testStress
 4. Include comprehensive documentation
 5. Update CI configuration if needed
 
+## Commit Message Guidelines
+
+We follow Conventional Commits format for all commit messages.
+
+### Format
+
+```
+type(scope): description
+
+[optional body]
+
+[optional footer]
+```
+
+### Types
+
+- `feat`: New feature
+- `fix`: Bug fix
+- `docs`: Documentation changes
+- `chore`: Maintenance tasks (dependencies, tooling)
+- `refactor`: Code restructuring without behavior change
+- `test`: Test additions or modifications
+- `perf`: Performance improvements
+- `ci`: CI/CD configuration changes
+- `revert`: Revert previous commit
+
+### Examples
+
+```
+feat(channels): add MPSC support
+fix(async): correct polling timeout in recv()
+docs: update README with verified benchmark data
+chore: bump Nim version to 2.2.0
+perf(channels): optimize ring buffer allocation
+```
+
+### Scope
+
+Optional but recommended. Indicates the module affected:
+- `channels`: Channel-related changes
+- `async`: Async/await functionality
+- `benchmarks`: Performance benchmarks
+- `tests`: Test infrastructure
+
+### Enforcement
+
+A commit-msg hook validates format automatically. See `.github/COMMIT_GUIDELINES.md` for details.
+
 ## Code Style
 
 ### Naming Conventions