perf: stop Tribe list and care summary from scanning the whole contact table (#6024)

[atomantic]

Summary

Two Tribe read paths were paying for data nothing consumed.

listPeople() ran two correlated COUNT(*) subqueries per person row — one over tribe_touchpoints, one over tribe_memory_links — so a 200-contact install did 400 extra index scans on every Tribe page load, every identity-resolution context load, and every contact-sync pass. Neither touchpointCount nor linkedMemoryCount is read anywhere in client/src/. The subqueries are gone; rowToPerson already defaults both to 0 when the columns are absent, and getPerson(id) still hydrates them for the detail view.

getCareSummary(limit) answered "who is overdue" by calling listPeople() with no filter — hydrating notes, next_move, and the tags / emails / phones arrays for every contact (plus those 2N subqueries) only to discard all of it in JavaScript. It now issues its own lean query for the six columns the cadence math and the response actually use, with the external exclusion pushed into SQL:

SELECT id, name, ring, cadence_days, last_contact_on, channel
FROM tribe_people
WHERE deleted = FALSE AND ring <> 'external'

ring is NOT NULL DEFAULT 'tribe', so moving the exclusion into SQL matches the previous JS filter exactly. This is the hotter of the two paths: it runs on every Dashboard mount and on the proactive-alerts poll every two minutes.

Response shape and ordering of GET /api/tribe/people and GET /api/tribe/care are unchanged.

Test plan

• cd server && npm test — full suite green (1917 files, 38679 tests).
• server/services/tribe.test.js extended:
  • listPeople asserts no COUNT(*) / tribe_touchpoints / tribe_memory_links in the SQL, that the ring-rank → oldest-contact → name ordering is intact, and that rows still map to full person objects with both counts defaulted to 0.
  • getPerson asserts the counts are still hydrated from its own subqueries.
  • getCareSummary asserts the lean column projection plus the ring <> 'external' / deleted = FALSE predicate, keeps the missing-first → most-overdue ordering case, pins the exact key set of each overdue item (id, name, ring, channel, lastContact, state, daysOverdue), and covers a Date-typed last_contact_on rendering to an ISO date string.
  • Both new SQL assertions fail against the pre-change queries.
• No *.db.test.js covers Tribe, so nothing DB-backed needed to run.

Closes #6024

https://claude.ai/code/session_01VjkWVTfzKyRuAv3HEsspwN