feat: 实现统一错误处理系统 (003-error-handling)

- 新增统一错误码定义和管理 (pkg/errors/codes.go)
- 新增全局错误处理器和中间件 (pkg/errors/handler.go, internal/middleware/error_handler.go)
- 新增错误上下文管理 (pkg/errors/context.go)
- 增强 Panic 恢复中间件 (internal/middleware/recover.go)
- 新增完整的单元测试和集成测试
- 新增功能文档 (docs/003-error-handling/)
- 新增功能规范 (specs/003-error-handling/)
- 更新 CLAUDE.md 和 README.md

specs/003-error-handling/checklists/requirements.md

@@ -0,0 +1,42 @@
+# Specification Quality Checklist: Fiber 错误处理集成
+
+**Purpose**: Validate specification completeness and quality before proceeding to planning  
+**Created**: 2025-11-14  
+**Feature**: [spec.md](../spec.md)
+
+## Content Quality
+
+- [x] No implementation details (languages, frameworks, APIs)
+- [x] Focused on user value and business needs
+- [x] Written for non-technical stakeholders
+- [x] All mandatory sections completed
+
+## Requirement Completeness
+
+- [x] No [NEEDS CLARIFICATION] markers remain
+- [x] Requirements are testable and unambiguous
+- [x] Success criteria are measurable
+- [x] Success criteria are technology-agnostic (no implementation details)
+- [x] All acceptance scenarios are defined
+- [x] Edge cases are identified
+- [x] Scope is clearly bounded
+- [x] Dependencies and assumptions identified
+
+## Feature Readiness
+
+- [x] All functional requirements have clear acceptance criteria
+- [x] User scenarios cover primary flows
+- [x] Feature meets measurable outcomes defined in Success Criteria
+- [x] No implementation details leak into specification
+
+## Notes
+
+所有检查项均通过。规范已完整定义错误处理功能的需求:
+
+- **User Scenarios**: 定义了 4 个优先级明确的用户故事,涵盖统一错误响应、Panic 恢复、错误分类和错误追踪
+- **Functional Requirements**: 10 条功能需求明确且可测试
+- **Success Criteria**: 8 条成功标准均为可度量的结果指标
+- **Edge Cases**: 识别了 6 个边界情况
+- **Technical Requirements**: 与项目架构规范保持一致
+
+规范已准备好进入下一阶段 (`/speckit.plan`)。