feat: add CI format check, flaky test handling, and enhanced onboarding docs

[abhishyantkhare]

Summary

This PR adds targeted CI/CD improvements and significantly enhanced onboarding documentation for the Twenty monorepo.

Original Task

Please analyze my connected GitHub repository and set up comprehensive CI/CD and documentation. Detect the project type, add missing CI checks (ESLint, tests, linting), and generate CLAUDE.md and AGENTS.md files with coding standards and guidelines.

Health Analysis Results (Score: 16/18 — 89%)

Category	Score	Details
Style & Validation	5/6	ESLint v9, Prettier, Husky — added CI format check
Build System	3/3	Nx workspace, Yarn 4, multi-layer caching
Testing	3/4	1,221 test files — added flaky test retry handling
Documentation	2/3	README + PR template — significantly enhanced CLAUDE.md + AGENTS.md
Security	4/5	CodeQL, Dependabot, Dependency Review
CI Workflows	4/4	24+ active workflows + new format check

Changes

New: `.github/workflows/ci-format.yaml`

• Prettier format check for all PRs and merge groups
• Uses existing `changed-files.yaml` reusable workflow for skip detection
• Uses existing `nx-affected` custom action for targeted checking
• Runs `fmt` target on both `scope:frontend` and `scope:backend` packages
• Follows the same status-check pattern as `ci-shared.yaml`

Enhanced: `CLAUDE.md`

• CI/CD Pipeline Overview table (14 CI + 2 CD + reusable workflows)
• Pre-commit Hooks documentation (Husky v9 + lint-staged)
• Pre-PR Checklist: lint → typecheck → format → test
• Custom ESLint Rules documentation (all 16 custom rules)
• Testing Guide (unit, integration, E2E, Storybook)
• Deployment Architecture (Render services, Docker, preview environments)

Enhanced: `AGENTS.md`

• CI/CD Automated Checks Table
• Custom ESLint Rules Summary (8 most impactful rules)
• Code Review Checklist (quality, security, testing, CI compliance, database/API)
• Preview Environment documentation
• Coding Standards (TypeScript best practices, Nx module boundaries, naming conventions)

New: Flaky Test Handling

• `packages/twenty-front/setupTests.ts`: Added `jest.retryTimes(2)`
• `packages/twenty-server/setupTests.ts`: Added `jest.retryTimes(2)`

Type of Change

• New CI workflow (format check)
• Test infrastructure improvement (flaky test retry)
• Documentation enhancement
• No breaking changes

[github-actions]

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[github-actions]

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