Warroom run summary — blank-extension-page (2026-05-11)

Dispatch trace

Wave	Agent	Run id	Status	Output
1a	toby-frontend-doctor	`6e2b3eb9-36bf-42d3-8de3-5afa48f4b167`	succeeded	Root cause at `Toby.tsx:304`; defers to backend
1b	toby-backend-doctor	`083ec6d2-63e9-4c3e-b55e-a95301a4aa72`	succeeded	Refutes SW-boot-regression; backend innocent
2 (coord)	toby-incident-coordinator	(this run)	—	Synthesised root cause + 3-layer FE fix
3	toby-incident-validator	`a28a3690-38d7-4ce9-a9c2-c6d436da1793`	succeeded	Validated, high confidence; 3 non-blocking follow-ups

Root cause: apps/extension/app/containers/Toby.tsx:304 returns null forever when isUserHydrated (added 2026-04-09 in d68726b29) never flips. getUser() at state/accessors/user.tsx:45-50 is unbounded; Chrome's "extension context invalidated" state drops the chrome.storage.local.get callback on every extension auto-update.
Fix: FE-only, defence-in-depth — bounded hydration promise (5s timeout, fail open), visible recovery screen after 8s ("Your tabs are safe. Tap to recover."), telemetry beacon.
Backend NOT implicated. Prod-api SHA 4b0107858 unchanged since 2026-02-02; 0 5xx in last 24h. Earlier MV3-SW-boot-regression hypothesis (388c1db4) refuted.

Every spawn_agent_run was paired with wait_for_run. Three children, three terminal-status waits, all succeeded before publication.