Mock server infrastructure

[kentcdodds]

Migrate the Resend mock to a Cloudflare Worker with D1, add a mock dashboard, and integrate mock server deployments into PR previews.

This improves mock server infrastructure, provides better visibility into mock state, and enables PR deploys to use dedicated, secure mock services.

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Note

Medium Risk
Moderate risk due to substantial CI workflow restructuring (new validate gating and new preview deploy/cleanup paths) and a new D1-backed mock Worker that changes how local dev and tests interact with mocked external services.

Overview
Mock infrastructure is now Worker-based and preview-deployable. The Resend mock is migrated from the old Bun createMockApiServer approach to a dedicated Cloudflare Worker (mock-servers/resend) that persists messages in D1, enforces an optional MOCK_API_TOKEN, and exposes a small /__mocks dashboard + metadata/message APIs; the legacy tools/mock-*.ts modules and the prior server/email/resend.test.ts are removed and replaced with new mock-worker tests.

CI/CD is reorganized around validation, production deploy gating, and preview stacks. A new ✅ Validate workflow runs lint/typecheck/tests/e2e, production deploy (deploy.yml) is triggered only on successful validation and guarded to deploy only the validated SHA at main HEAD, and a new preview.yml deploys/cleans up per-PR (or manual) preview Workers plus per-mock Workers, wiring the app preview to those mock URLs via generated secrets. Secret syncing is consolidated via a new tools/ci/sync-worker-secrets.ts wrapper around wrangler secret bulk, and local dev (cli.ts) now starts the Resend mock via wrangler dev (dev:mock-resend) and waits for readiness.

Docs and setup tooling are updated accordingly: adds .env.example for preview/local defaults, expands docs/post-download.ts to update preview workflow + mock worker configs, and updates TypeScript worker config to include mock-servers/**.

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[github-actions]

🔎 Preview deployed: https://epicflare-pr-27.kentcdodds.workers.dev

Worker: epicflare-pr-27

Mocks:

• resend: https://epicflare-pr-27-mock-resend.kentcdodds.workers.dev (epicflare-pr-27-mock-resend)

[cursor]

Bugbot Autofix prepared fixes for 2 of the 2 bugs found in the latest run.

• ✅ Fixed: Deploy overwrites optional Resend secrets
  • Guarded production secret sync to only update Resend values when the GitHub secrets are non-empty.
• ✅ Fixed: Manual preview runs share one concurrency group
  • Adjusted the preview workflow concurrency group to include workflow dispatch inputs so manual runs no longer collide.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

[cursor]

Empty --env string passed to wrangler breaks previews

High Severity

The runWranglerSecretBulk guard at line 224 checks options.env !== undefined, which is true when options.env is "". This causes --env "" to be forwarded to wrangler, which may fail because an empty string is not a valid environment name. The label logic at line 258 (options.env && options.env.length > 0) correctly treats empty string as "default," revealing the author's intent — but the wrangler argument guard doesn't match. Both preview workflow calls (--env "" on lines 155 and 199) would be affected, potentially breaking all preview deploys.

Additional Locations (1)

• .github/workflows/preview.yml#L154-L155