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/04-开发规范/01-数据库设计规范.md

@@ -495,3 +495,4 @@ content TEXT               -- 内容
 
 
 
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docs/04-开发规范/02-API设计规范.md

@@ -525,3 +525,4 @@ If-None-Match: "33a64df551425fcc55e4d42a148795d9f25f89d4"
 
 
 
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docs/04-开发规范/03-数据库全局视图.md

@@ -347,3 +347,4 @@ CREATE TABLE ssa_schema.analysis_projects (
 
 
 
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docs/04-开发规范/04-API路由总览.md

@@ -391,3 +391,4 @@
 
 
 
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docs/04-开发规范/06-Git提交规范.md

@@ -855,3 +855,4 @@ git push-current # 推送当前分支
 **版本历史：**
 - v1.0 (2025-11-16): 初始版本，包含完整的 Git 规范和中文乱码解决方案
 
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