[ BOUNTY] [Docs] Create CONTRIBUTING.md with build instructions and PR workflow

[soongyintong]

Summary

This PR creates CONTRIBUTING.md for the zeroeye/Tent of Trials project, providing a comprehensive contributor guide covering local setup, build instructions, PR submission workflow, code style, and bounty guidelines.

Changes

• Created CONTRIBUTING.md with:
  • Full setup instructions for all 10 modules (Rust, TypeScript, Go, C, C++, Java, Ruby, Lua, Haskell)
  • Build validation workflow using python3 build.py
  • Pull request process with step-by-step instructions
  • Quick checklist for bounty submissions
  • Git commit message conventions
  • Module-specific build commands
  • Links to existing docs (ARCHITECTURE.md, API_REFERENCE.md, CHANGELOG.md)
  • Reference to .github/pull_request_template.md
• Diagnostic build artifacts included (build-db991709.logd, build-db991709.json)

Testing

Ran python3 build.py to validate the build pipeline. Diagnostic logs are committed as required.

Checklist

• Relevant modules affected by these changes build locally
• Tests pass locally (documentation change — no tests affected)
• Diagnostic build log is committed in this PR
• Documentation has been updated (new CONTRIBUTING.md added)
• Configuration or schema changes are documented, if applicable
• No generated build artifacts are committed, except the required diagnostic build log
• Changes are scoped to the PR purpose and avoid unrelated cleanup
• Security, privacy, and error-handling implications have been considered