Introduce Minimal Service Worker Registration Surface

[FlorianRappl]

Proposal

Provide a practical subset of Service Worker APIs to support registration and fetch interception workflows.

Scope:

• Add navigator.serviceWorker getter.
• Support register, getRegistration, and getRegistrations.
• Model registration state transitions at a minimal level.
• Provide integration hook for request/fetch interception.
  Technical Notes:
• Use in-memory registration store keyed by origin and scope.
• Keep execution/runtime behavior abstracted behind platform adapters.
  Acceptance Criteria:
• Registering a worker creates retrievable registrations by scope.
• Scope matching behaves consistently.
• Fetch pipeline can be wired to registration hooks.
• Tests verify lifecycle and scope behavior.
  Out of Scope:
• Full event loop/task semantics of production browsers.
• Full worker script runtime.

Description

Introduce a minimal Service Worker registration surface on navigator.serviceWorker, including register, getRegistration, and getRegistrations, plus basic scope handling and lifecycle state tracking.

Background

Service Worker registration is foundational for modern offline/network interception flows. Even without a full worker runtime, registration-level support unlocks realistic app bootstrapping and controlled fetch routing scenarios.

Specification

• Service Workers specification: https://w3c.github.io/ServiceWorker/
• Focus area: ServiceWorkerContainer and registration lifecycle primitives