P1.9: loadDeviceSettings / loadBlacklist / saveBlacklist / saveDeviceSettings + itemToManifestEntry were duplicated across popup-only.ts and content-callable.ts. Lifts the four storage helpers into service-worker/ storage.ts and itemToManifestEntry into service-worker/vault.ts. Both router files now import from one home each. Adds storage.test.ts covering round-trips and defaults. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>