feat(schema): add geographic eligibility to programs

[teddiesloco]

Summary

• add optional geographic and jurisdictional eligibility fields to the program JSON schema
• preserve eligibility through the registry/API mapping and expose typed camelCase fields in the SDK
• show eligibility details in CLI info output and advertise them in the MCP get_program tool
• add Ajv schema regression coverage for a populated eligibility block and the existing YAML corpus

Validation

• npm test
• npm run lint (0 errors; 23 pre-existing warnings)
• npm run lint --workspace openaffiliate-sdk
• npm run lint --workspace openaffiliate
• npm run lint --workspace openaffiliate-mcp
• npm run registry:build (760 programs)
• npm run build (884 static/dynamic routes generated)
• npm run build for SDK, CLI, and MCP workspaces

Closes #27

[vercel]

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