this PR puts sync stuff in the bemo worker, and sets up a temporary
dev-only page in dotcom for testing bemo stuff
### Change type
- [ ] `bugfix`
- [ ] `improvement`
- [x] `feature`
- [ ] `api`
- [ ] `other`
### Test plan
1. Create a shape...
2.
- [ ] Unit tests
- [ ] End to end tests
### Release notes
- Fixed a bug with...
Sets up preview deploys etc. for bemo worker.
There's enough going on here that I wanted to make it its own PR. I'll
rework david's spike on top of it once it's landed.
### Change Type
- [x] `internal` — Does not affect user-facing stuff
- [x] `chore` — Updating dependencies, other boring stuff
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Co-authored-by: David Sheldrick <d.j.sheldrick@gmail.com>