test(transport): consolidate duplicate iOS routing and startup fixtures

Both app-core and UI suites drive the same shared iOS transport implementation through app-core's forwarding export, but eight routing cases execute twice. The app-core versions already include stronger no-kernel-effect assertions and long-path coverage. Watchdog mode, relative-URL identity, and startup trace fixtures repeat setup within the host suite.

Consolidate duplicates into existing owners without moving all suites or building another harness. Preserve the UI dynamic hostile-proxy and boot-progress cases, the distinct primed-runtime thenable entry, store/cloud network policy, request translation, and cross-entrypoint shared restart behavior. Convert the native bridge identity-only assertion to an actual bridged request in an existing flow.

Acceptance: both package baselines and retained suites, meaningful routing fault detection with production restored, package types/read-only lint, root verification. This changes tests only; no renderer, native binary or runtime behavior changes. Device screenshots/live model/visual evidence are N/A for test-fixture consolidation and these simulated bridge tests do not certify installed iOS behavior.

Implemented locally in cc03c357b5: 94 additions / 319 deletions, 225 net removed. Retained UI2 + host37 tests pass; adjacent13fetch cases pass under shuffled order. Both package types/read-only lint pass. Remote-routing fault is caught by both real fetch flows; production restored. Full root verify passes after separate build prerequisite fix15a1c08c95:377tasks and all later audits. Local completion only; scoped delivery remains open.