Rewrite workshop 10: Conclusion: target model and build plan #337

Part of #326.

Questions

• Target data model and API in one page
• Every current table, route group, Studio app and phone screen mapped to "kept as", "replaced by" or "deleted"
• Teardown list and build order, as a new build epic with sub-issues
• Staging-first rollout; production data is dropped
• Checklist item: the owner downloads /photos from the production media bucket before the buckets are deleted

As-is sources

all decision pages

Format

No product code. I prepare docs/rewrite/10-conclusion.md with the as-is state (with file paths), the problems and leaks, a proposal and the open questions; mockups go to docs/rewrite/mockups/. The owner decides, the decisions are recorded in the page's "Decided" section and here, and the PR is merged into rewrite/plan.