新增 test/PHASE2_TEST_PLAN.md,详细规划上线后测试补齐路径: **P0 优先级(2周内)**: - memory/postgres store 达标 >60% - router/health handler 达标 >60% - handlers 补齐 HandleChannel/TicketStatsHandler.Get **P1 优先级(4周内)**: - Domain 包(6个)基础测试 >30% - logging/dialog/app 提升至 >75% **Phase 2 目标**:整体覆盖率从 62.6% → >70% Ref: PRODUCTION_PHASE1_STATUS.md §8 测试覆盖率