- Wrote the required docs/specs: `docs/prd.md:1`, `docs/acceptance-criteria.md:1`, `docs/architecture/domain-model.md:1`, `docs/api-contracts.md:1`, `docs/test-strategy.md:1`, `docs/handover.md:1`, `specs/invariants.md:1`, and updated `README.md:1`.
- Implemented pure TS domain core (entities, invariants, opportunity stage transitions, dashboard summary): `packages/domain/src/index.ts:1`.
- Implemented in-memory CRM API/service (referential integrity, orchestration, dashboard summary) + re-exports: `packages/api/src/index.ts:1`.
- Added focused tests: `packages/domain/test/entityFactories.test.ts:1`, `packages/domain/test/opportunityStageTransitions.test.ts:1`, `packages/domain/test/dashboardSummary.test.ts:1`, `packages/api/test/inMemoryCrm.test.ts:1`.
- Verified the workspace passes: `npm run lint`, `npm run typecheck`, `npm run test`.