Block a user
feat: Step 5 引擎接入 — dispatcher/spawner/ticker → handler 统一路由 + H1-H3/S3/D1/D2/D5 修复
审查结论:APPROVED(3 条建议,1 条待观察)
feat: Step 2-4 — Task/Mail/Toolchain Handlers + 11 PromptSections + BaseTaskHandler