Merges FN-3306 agent detail favorites wiring and test coverage, FN-3244 mobile FAB drag path hardening, FN-3303 mobile split layout updates, FN-3366 CI shard contract documentation with a new `scripts/ci-test-shard.mjs`, and FN-3014 research recovery semantics — plus expanded research extension tool Fusion-Task-Id: FN-3306