fix: use user_id/current_score in scoresService bulk queries

[flare-999]

Overview

updateUserScoresBulk and setAbsoluteUserScoresBulk in backend/src/services/scoresService.ts wrote to scores (borrower, score) and used ON CONFLICT (borrower), but the scores table created by 1771691269865_initial-schema.js has user_id and current_score. Every bulk score update therefore failed with column "borrower" of relation "scores" does not exist, crashing score updates and background reconciliation.

Related Issue

Closes #1800

Changes

• [MODIFY] backend/src/services/scoresService.ts

  • updateUserScoresBulk: INSERT INTO scores (user_id, current_score) ... ON CONFLICT (user_id), and the conflict branch now clamps scores.current_score + EXCLUDED.current_score - 500.
  • setAbsoluteUserScoresBulk: reconciliation CTE renamed to reconciled_scores (user_id, current_score), inserts into scores (user_id, current_score) with ON CONFLICT (user_id) and sets current_score = EXCLUDED.current_score.

• [MODIFY] backend/src/services/__tests__/scoresService.test.ts

  • Updated the SQL assertion from ON CONFLICT (borrower) to ON CONFLICT (user_id).

• [MODIFY] backend/src/__tests__/scoresService.test.ts

  • The DB-backed suite created a legacy scores (borrower, score) fixture; it now creates/reads user_id / current_score so it exercises the real schema.

• [MODIFY] backend/src/__tests__/migration.test.ts

  • Score insert/select/delete helpers now use user_id / current_score.

Verification Results

Implemented via GitHub Contents/Git API (no local clone).
Acceptance criteria mapping:
The SQL in scoresService.ts now targets user_id / current_score (both bulk functions)
No remaining `borrower` / `score` column references in scoresService.ts
The DB-backed and migration tests were aligned with the real `scores` schema

Acceptance Criteria	Status
SQL queries use user_id and current_score	updateUserScoresBulk and setAbsoluteUserScoresBulk both updated
ON CONFLICT targets an existing unique column	ON CONFLICT (user_id) (unique per initial-schema migration)
No regression in unit assertions	scoresService.test.ts expectation updated

[flare-999]

@LabsCrypt both failing checks are green now.

Before: backend, env-docs-check
After: both pass.

Root cause & fix

• backend failed on the new query() calls in backend/src/services/scoresService.ts because they weren't wrapped the way prettier/prettier requires — reformatted the call sites (no behavioural change).
• env-docs-check is the env-documentation guard: the branch was behind main, so the documented env vars didn't match the current code. Merging main in brought the branch's docs/code back in sync, and the guard passes.

Head c5da1c941f → 280e4cb97a.