Generate msw handlers from each spec alongside the client

[ExtraToast]

What to build

Mock handlers are generated from each spec and published alongside the client, so tests mock the contract instead of a hand-written guess.

Today mocking is done three incompatible ways: a declared but entirely unused interception library in two applications, a large hand-written route mock file with hand-typed fixtures in a third, and module-level mocking of the generated client in unit tests — which means no test exercises transport, base URL, auth headers or CSRF.

Generated handlers become the default because a contract change should move the mocks, and because per-test overrides are what stateful login and streaming flows need.

Acceptance criteria

• Handlers are derived from the spec and shipped with the client
• A single response can be overridden per test without abandoning the generated set
• Handlers work both in component tests and in the browser-driven suite
• Regenerating produces no diff when the spec has not changed

Blocked by

• Emit TanStack Vue Query artifacts behind a subpath export