Add CLAUDE.md documentation file

[ilikesymmetry]

Summary

Add comprehensive CLAUDE.md documentation file to provide project context and development guidance for Claude Code users.

Changes

• New file: CLAUDE.md with comprehensive project documentation
• Includes project overview explaining the Commerce Payments Protocol
• Documents core concepts: authorization/capture flow, operators, token collectors
• Lists all development commands (testing, building, deployment)
• Provides current deployment addresses for Base networks
• Includes security audit information and key dependencies
• Adds contributing guidelines and environment setup instructions

Test plan

• File created with proper formatting
• All development commands verified against CI workflow
• Deployment addresses match current README
• Documentation structure follows project conventions

[cb-heimdall]

✅ Heimdall Review Status

Requirement	Status	More Info
Reviews	✅ 1/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1