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/epic5/README.md

@@ -1,7 +1,9 @@
 # Epic 5: Infrastructure Adapters
 
 ## Overview
-Implement infrastructure adapters (cache, queue, blob storage, email), make adapters swappable via interfaces, add scheduler/background jobs system, and implement event bus (in-process and Kafka).
+Implement infrastructure adapters (cache, queue, blob storage, email) that services use. These adapters are shared infrastructure components that all services can use. Make adapters swappable via interfaces, add scheduler/background jobs system, and implement event bus (in-process and Kafka).
+
+**Note:** gRPC service definitions and clients are already implemented in Epic 1 (Story 1.7) and Epic 2 (each service implements its own gRPC server). Story 5.7 focuses on advanced gRPC features and enhancements.
 
 ## Stories
 
@@ -35,10 +37,12 @@ Implement infrastructure adapters (cache, queue, blob storage, email), make adap
 - **Goal:** Implement secret store integration supporting Vault and AWS Secrets Manager.
 - **Deliverables:** Secret store interface, Vault implementation, AWS implementation, config integration
 
-### 5.7 gRPC Service Definitions and Clients
-- [Story: 5.7 - gRPC Services](./5.7-grpc-services.md)
-- **Goal:** Implement gRPC service definitions and clients to enable microservices communication.
-- **Deliverables:** gRPC service definitions, gRPC servers, gRPC clients, code generation
+### 5.7 Advanced gRPC Features
+- [Story: 5.7 - Advanced gRPC Features](./5.7-grpc-services.md)
+- **Goal:** Enhance gRPC implementation with advanced features (streaming, advanced error handling, gRPC-Gateway).
+- **Deliverables:** Streaming RPCs, gRPC-Gateway integration, advanced error handling, gRPC middleware
+
+**Note:** Basic gRPC service definitions and clients are already implemented in Epic 1 (Story 1.7) and Epic 2 (each service implements its own gRPC server).
 
 ## Deliverables Checklist
 - [ ] Cache adapter (Redis) working
@@ -47,7 +51,7 @@ Implement infrastructure adapters (cache, queue, blob storage, email), make adap
 - [ ] Email notification system
 - [ ] Scheduler and background jobs
 - [ ] Secret store integration (optional)
-- [ ] gRPC service definitions and clients
+- [ ] Advanced gRPC features (streaming, gRPC-Gateway)
 
 ## Acceptance Criteria
 - Cache stores and retrieves data correctly
@@ -55,4 +59,6 @@ Implement infrastructure adapters (cache, queue, blob storage, email), make adap
 - Files can be uploaded and downloaded
 - Email notifications are sent
 - Background jobs run on schedule
+- gRPC streaming works
+- gRPC-Gateway provides HTTP access to gRPC services
 - Integration test: full infrastructure stack works