[$30 BOUNTY] [Docs] Create CONTRIBUTING.md with build instructions

[cuentaprueba244w-dotcom]

Bounty: $30 (LT)

Area: CONTRIBUTING.md - contributor guide

Current state: No contributor guide exists.

What's needed: Write CONTRIBUTING.md with local setup, build instructions, and PR submission guidelines.

Acceptance criteria:

• Covers cloning, dependencies, build commands
• Describes PR workflow: fork > branch > commit > PR
• Links to pull_request_template.md
• References .editorconfig for code style

Required validation:

• Run python3 build.py
• Include the generated diagnostic .logd artifact from diagnostic/build-XXX.logd in the PR; also include diagnostic/build-XXX.json if present
• Use .github/pull_request_template.md for your submission

[Luzijano]

I'm taking this one now and will submit a scoped PR with the required diagnostics.

[zjwjing]

I would like to work on creating CONTRIBUTING.md.

Plan:

1. Review project structure and README
2. Create comprehensive CONTRIBUTING.md with:
   • Local setup instructions
   • Build commands for all modules
   • PR workflow (fork > branch > commit > PR)
   • Links to pull_request_template.md
   • Reference to .editorconfig
3. Run python3 build.py and include diagnostic artifacts

Wallet: 0x8971bC40f06e90015C5e92d247c96BfB65C24Cc7