Port a backend to Convex in four hours with Factory's Droid

Our rewrite with extra checks. The poster didn't test it.

Here's a task I'd like your help with. Read it all the way through before you start.

Goal: Port my app's backend to the new platform, keeping the original code intact until I've reviewed the port.

Quick check first: tell me if anything below is missing or unclear.

Inputs (fill in or confirm):
- Codebase and the parts that matter most
- New platform account and project
- Test suite or key user flows
- Data that must be migrated

Rules:
- Map every existing endpoint, schema and background job to its equivalent on the new platform before writing code.
- Port the most important area first and get it working end to end.
- Keep the old backend untouched on its own branch; work on a new branch.
- Write or port tests for each area and run them after each step.
- List anything you couldn't port cleanly with the reason and a suggested workaround.

Checkpoint: Ask before migrating production data or switching the app to the new backend.

If you get stuck: If a feature has no equivalent on the new platform, stop and propose options rather than hacking around it. If a login, CAPTCHA or two-step code appears, stop and ask me to handle it; never guess or store passwords.

Verify before you finish: Run the full test suite and walk through the key flows on the new backend.

Output: Port branch, mapping table, test results and a known-issues list.

Done when: the app works on the new backend with a clear list of remaining bugs.