chore: move CONTRIBUTE.md to repo root as CONTRIBUTING.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/CONTRIBUTE.md

@@ -1,59 +0,0 @@
-# Contributing
-
-Thanks for your interest in MimiClaw. This project welcomes focused, high-quality contributions that improve reliability, performance, or documentation.
-
-## Scope
-
-We accept contributions in these areas:
-
-- Core firmware features and bug fixes
-- Documentation, examples, and diagrams
-- Build and tooling improvements
-- Tests and CI enhancements
-
-> **External Peripherals**
-> We are not accepting PRs that add or change external peripherals right now.
-
-## Before You Start
-
-- Search existing issues and discussions to avoid duplication.
-- Open a short proposal for large or risky changes.
-- Keep changes small and reviewable when possible.
-
-## Development Setup
-
-- Install ESP-IDF v5.5+.
-- Build targets are in `idf.py`.
-- Default config lives in `main/mimi_secrets.h.example`.
-
-## Branching and Commits
-
-- Use a short, descriptive branch name.
-- Keep commit history clean and focused.
-- Suggested commit style: `docs: ...`, `fix: ...`, `feat: ...`.
-
-## Pull Requests
-
-- Describe the problem and the solution clearly.
-- Include testing steps and results.
-- Update documentation when behavior changes.
-
-## Code Style
-
-- Match existing naming and formatting.
-- Prefer clarity over cleverness.
-- Avoid large refactors mixed with functional changes.
-
-## Tests
-
-- Add or update tests when behavior changes.
-- If tests are not available, explain why and how you validated the change.
-
-## Documentation
-
-- Keep README and docs in sync with behavior changes.
-- Add concise examples for new features.
-
-## License
-
-By contributing, you agree that your contributions will be licensed under the MIT License.