docs: Align documentation with true microservices architecture

Transform all documentation from modular monolith to true microservices
architecture where core services are independently deployable.

Key Changes:
- Core Kernel: Infrastructure only (no business logic)
- Core Services: Auth, Identity, Authz, Audit as separate microservices
  - Each service has own entry point (cmd/{service}/)
  - Each service has own gRPC server and database schema
  - Services register with Consul for service discovery
- API Gateway: Moved from Epic 8 to Epic 1 as core infrastructure
  - Single entry point for all external traffic
  - Handles routing, JWT validation, rate limiting, CORS
- Service Discovery: Consul as primary mechanism (ADR-0033)
- Database Pattern: Per-service connections with schema isolation

Documentation Updates:
- Updated all 9 architecture documents
- Updated 4 ADRs and created 2 new ADRs (API Gateway, Service Discovery)
- Rewrote Epic 1: Core Kernel & Infrastructure (infrastructure only)
- Rewrote Epic 2: Core Services (Auth, Identity, Authz, Audit as services)
- Updated Epic 3-8 stories for service architecture
- Updated plan.md, playbook.md, requirements.md, index.md
- Updated all epic READMEs and story files

New ADRs:
- ADR-0032: API Gateway Strategy
- ADR-0033: Service Discovery Implementation (Consul)

New Stories:
- Epic 1.7: Service Client Interfaces
- Epic 1.8: API Gateway Implementation

docs/content/stories/README.md

@@ -12,14 +12,14 @@ Tasks are organized by epic, with each major task section having its own detaile
 ### Epic 1: Core Kernel & Infrastructure
 - [Epic 1 Tasks](./epic1/README.md) - All Epic 1 tasks
 
-### Epic 2: Authentication & Authorization
-- [Epic 2 Tasks](./epic2/README.md) - All Epic 2 tasks
+### Epic 2: Core Services (Authentication & Authorization)
+- [Epic 2 Tasks](./epic2/README.md) - Auth, Identity, Authz, Audit as independent services
 
-### Epic 3: Module Framework
-- [Epic 3 Tasks](./epic3/README.md) - All Epic 3 tasks
+### Epic 3: Module Framework (Feature Services)
+- [Epic 3 Tasks](./epic3/README.md) - Module framework for feature services
 
-### Epic 4: Sample Feature Module (Blog)
-- [Epic 4 Tasks](./epic4/README.md) - All Epic 4 tasks
+### Epic 4: Sample Feature Service (Blog Service)
+- [Epic 4 Tasks](./epic4/README.md) - Blog Service as reference implementation
 
 ### Epic 5: Infrastructure Adapters
 - [Epic 5 Tasks](./epic5/README.md) - All Epic 5 tasks