feat: add production templates API and documentation for manufacturing phase 2

- Implemented CRUD operations for production templates, including listing, retrieving, creating, updating, and deactivating templates.
- Introduced a new API contract for production runs, detailing the lifecycle from creation to completion, including handling of stock inputs and outputs.
- Documented the architecture, requirements, entity model, and API contract for the manufacturing phase 2, ensuring clarity on the production process and its integration with existing systems.

docs/00-CORE.md

@@ -342,6 +342,8 @@ All frontend work is governed by `20-FRONTEND.md`.
 | HRM API endpoints, request/response shapes, error catalog (Phase 2) | **`13-BACKEND-HRM-API.md`** |
 | Frontend user-flows, screen flow, architecture rules, validation posture (Phase 1) | **`20-FRONTEND.md`** |
 | HRM frontend user-flows (Phase 2) | **`21-FRONTEND-HRM.md`** |
+| Manufacturing requirements, business rules, entities, stock/costing integration, API (Phase 2) | **`30-BACKEND-PHASE2.md`** |
+| Manufacturing frontend user-flows — template canvas, run board, run execution (Phase 2) | **`21-FRONTEND-PHASE2.md`** |
 | Security risks per feature, accepted-risk register, pre-ship checklist | **`02-SECURITY.md`** |
 | Understanding the doc system, reading order, tracking conventions | **`01-DOC-GUIDE.md`** |
 | Recording backend changes made | **`Backend/PROGRESS.md`** |