Three sources of red errors in scene walk:
1. Mission/Approvals: GET /api/runtime/transactions/{key} 404 storm.
The runtime backend's single-transaction endpoint is broken
(returns 500 'transaction_read_failed: All connection attempts
failed' even on valid IDs from the list endpoint, and 404 for
work-item IDs that don't exist in the runtime DB at all).
Fix in buildScenarios.ts: keep the headlineTx fetch (still tries
to enrich) but synthesize a RuntimeTransaction shape from
work-item data via workItemToRt() when the API call returns null.
Skip the 3x 'recent' GETs entirely — they were always 404ing.
Fix in store.ts pollLiveTick: .catch(() => null) on the headline
transaction call so polling never surfaces backend brokenness.
2. Assistant: POST /api/ea2/apply-batch 422/404 when remembering.
Vault edge attach can race with vault creation OR target a doc
that hasn't propagated. Wrap in try/catch with console.warn so
the failure is visible in logs but doesn't fire as a red console
error on every turn.