Add x402 environment configuration for main branch (production)

[crtahlin]

Summary

Add x402 environment configuration for main branch deployments, analogous to what was done for dev branch in #53 and #54.

Prerequisites: Test x402 on dev branch thoroughly before applying to main.

Current State

Dev branch (staging) has:

• Environment variables configured via GitHub staging environment
• Dockerfile upgraded to Python 3.10 (Upgrade Docker to Python 3.10+ for x402 SDK compatibility #55, Upgrade Docker to Python 3.10 for x402 SDK compatibility #56)
• x402 middleware enabled

Tasks

1. Create GitHub production environment (if not exists)
2. Modify deploy.yml to write env file for main branch (similar to dev)
3. Modify docker-compose.yml to add env_file to provenance_gateway service
4. Set production environment variables:
   • X402_ENABLED
   • X402_PAY_TO_ADDRESS (may be different from staging)
   • X402_NETWORK (likely base for mainnet, not base-sepolia)
   • X402_FACILITATOR_URL
   • X402_FREE_TIER_ENABLED

Files to modify

• .github/workflows/deploy.yml - Add env file step for main branch
• docker-compose.yml - Add env_file to main service

Notes

• DO NOT merge to main until dev testing is complete
• Production may use different network (base vs base-sepolia)
• Production wallet address should be reviewed before setting
• Consider if free tier should be enabled in production

Related

• Configure x402 environment variables for dev deployment #53 - Configure x402 environment variables for dev deployment
• Add x402 environment configuration for dev deployments #54 - PR that implemented dev config
• Upgrade Docker to Python 3.10+ for x402 SDK compatibility #55 - Python 3.10 upgrade for x402 SDK
• Upgrade Docker to Python 3.10 for x402 SDK compatibility #56 - PR that implemented Python upgrade

[crtahlin]

Status update: This is intentionally NOT done yet.

Prerequisites before enabling x402 on production (main branch):

1. ✅ Staging (dev) x402 testing complete
2. ⏳ CLI developer confirms payment flow works end-to-end
3. ⏳ Decide on production wallet address
4. ⏳ Decide if free tier should be enabled in production
5. ⏳ Choose network: base (mainnet) or keep base-sepolia (testnet)

DO NOT merge x402 to main until staging testing is fully validated.