fix(attio-sync): use PUT to overwrite related_people so shrinks converge

[detail-app]

Detail bug report: View on Detail

Bug

The Attio alumni-interactions sync never reached a fixed point for any entry whose relatedPersonEmails shrank. src/attio/sync/writeChanges.ts applied every list-entry update via PATCH /v2/lists/{list}/entries/{entry_id}, but Attio's PATCH endpoint for list entries is append-multiselect-only: supplied multiselect values are prepended and existing values are never removed. related_people is the only multiselect attribute the sync writes (scripts/attio-setup.ts sets isMultiselect: true).

When a mentor's relatedPersonEmails shrinks — a student rejected after their mentor's entry was already synced, dropped from the projection by AND s.status != 'REJECTED' in projectParticipations.ts — the removed reference could never take effect via PATCH. So the next run re-read the unchanged related_people, buildDiffPlan saw the same mismatch, and queued the identical PATCH again — re-PATCHing that entry every run indefinitely (non-convergence). The PATCH method had been chosen in the original "Add Attio sync" commit when only single-value scalar fields were in play (where append == overwrite), and was never revisited when 676a275 added the multiselect related_people field.

Fix

Route related_people through PUT (Attio's overwrite/remove-multiselect endpoint — same path and identical request-body schema as PATCH) whenever relatedPersonEmails is in changedFields. Scalar single-value fields stay on PATCH (the method established for them; Attio's PUT docs only spell out multiselect behavior, so the split keeps scalars on the well-understood method). A row changing both kinds issues both writes and is still counted as a single entriesUpdated. The record-reference value shape entryValuesFor already emits ({ target_object, target_record_id }) is accepted by both operations unchanged, so this is a pure method swap with no client-side transformation.

Testing

• Unit tests (offline, HTTP-stubbed, npx tsx): added four tests pinning the method choice and convergence. A relatedPersonEmails-only update uses PUT with a related_people-only body; a scalar-only update still uses PATCH with related_people absent; a mixed update splits into PUT(related_people) + PATCH(scalar) and counts as one update; and a multi-cycle convergence test exercises readAttioState → buildDiffPlan → writeChanges against a stateful mock implementing Attio's documented PATCH-prepend / PUT-overwrite semantics, confirming a shrunk reference is removed on cycle 1 and the entry reaches steady state on cycle 2. All pre-existing tests continue to pass (79 assertions, 0 failures).

• **Regression gate

• Typecheck (npx tsc --skipLibCheck --noEmit): clean (exit 0).

• Lint: not run to completion — ESLint is broken project-wide (@typescript-eslint/parser@3.10.1 is incompatible with typescript@5.2.2, failing on the first parse on unmodified files), and is not gated by CI.

• Live end-to-end: could not be verified. I started a Postgres server on a free port, applied the Prisma schema, and seeded the REJECTED-student scenario; Stage B (the DB projection) confirmed the expected shrink ({extra@example.com}, with the rejected student dropped). The live sync then reached Attio at Stage C (readAttioState) and was blocked by a 401 auth_error/unauthorized — a real Attio Admin-panel API token is required and unavailable in this environment. The create-path behavior is covered offline by the existing testRelatedPeopleResolvedAtWriteTimeAndUnresolvableDropped, which passed.

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