test: guard mock API module wiring against unmatched-block regressions (#382)

[JuliobaCR]

Summary

• lib/api/mock.ts previously reached EOF with an unmatched block delimiter (the error surfaced around the old resourceAccess return block, lines 2114-2117), breaking parsing of the module and, transitively, lib/api/index.ts and components/nav.tsx — the root route returned HTTP 500.
• The file was subsequently split into focused domain modules under lib/api/mock/*.ts (core, session, members, analytics, webhooks, approvals, social, moderation, governance, controls, scenarios, fixtures, state), aggregated by the MockAccessApi class in lib/api/mock.ts, which resolves the unmatched-delimiter parse failure as a side effect.
• This PR adds a regression test (test/mock-api-module-wiring.test.ts) that exercises the public API boundary and one method from each domain module, so a future wiring or parse regression in lib/api/mock.ts is caught by the test suite instead of surfacing as a root-route 500.

Verification

• npx tsc --noEmit on lib/api/mock.ts and lib/api/index.ts: no parse/syntax errors (only pre-existing, unrelated type errors from missing @types/node).
• New test passes: MockAccessApi module wiring (#382) — 2/2 passing (compiled and run in isolation against lib/api/mock.ts + lib/api/index.ts, since the full npm test run currently fails at the tsc -p test/tsconfig.json step on pre-existing, unrelated errors in other files — none in lib/api/mock* or this new test).

Test plan

• lib/api/mock.ts parses successfully
• lib/api/index.ts imports it without a syntax error
• New regression test added and passing
• Existing mock API return values/control flow unchanged (no production code modified — this PR only adds a test)

Closes #382