docs: Update architecture docs with platform infrastructure details

- Add platform infrastructure chapter to frontend-backend architecture design
- Update system architecture document with 6 new infrastructure modules
- Update AI onboarding guide with infrastructure overview
- Link to backend/src/common/README.md for detailed usage guide

Key Updates:
- Storage service (LocalAdapter + OSSAdapter)
- Logging system (Winston + JSON format)
- Cache service (Memory + Redis)
- Async job queue (Memory + Database)
- Health check endpoints
- Monitoring metrics
- Database connection pool
- Environment config management

All modules support zero-code switching between local and cloud environments.

Related: #Platform-Infrastructure

docs/_templates/API设计-模板.md

@@ -473,3 +473,4 @@ curl -X POST "http://localhost:3001/api/v1/xxx/resources" \
 
 
 
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docs/_templates/README.md

@@ -77,3 +77,4 @@
 
 
 
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docs/_templates/[AI对接] 快速上下文-模板.md

@@ -178,3 +178,4 @@ POST   /api/v1/[module]/[resource2]
 
 
 
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docs/_templates/数据库设计-模板.md

@@ -218,3 +218,4 @@ INSERT INTO xxx_schema.xxx_table_name (field_name, status) VALUES
 
 
 
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docs/_templates/模块README-模板.md

@@ -85,3 +85,4 @@
 
 
 
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