test(enterprise): verify D4 crash recovery

[Gracker]

Base PR: #102

Root commit: af2a0bf

Summary

• Add D4 to the enterprise multi-tenant window regression script.
• Verify the crash/restart contract keeps the leaseId stable while backend proxy targets avoid exposing the old internal trace_processor port.
• Mark README §0.7 D4 as checked.

Verification

• cd backend && npx jest --runInBand --forceExit src/scripts/tests/verifyEnterpriseMultiTenantWindows.test.ts
• cd backend && npx jest --runInBand --forceExit src/services/tests/traceProcessorLeaseProcessorRouting.test.ts src/routes/tests/traceProcessorProxyRoutes.test.ts
• cd backend && npm run typecheck
• git diff --check
• npm run verify:pr

[Gracker]

已通过 commit 67856ec (merge) + 023a84a (frontend rebuild) 合入 main，关闭此 PR。