chore: scaffold monorepo and migrate uhd_web design system (W0-A)

- pnpm workspace: apps/{web,server}, packages/{contracts,db,domain,adapters,tasks,agent,testkit}
- server: Hono + zod-openapi, API Key auth with scopes, redacting pino logger, SSE event bus with replay, worker heartbeat
- db: Kysely + pg, file migrator, 0001_init (settings/api_key/audit_event/outbox_event)
- web: React Router 7 SPA console shell with 12 workspace placeholders, uhd_web tokens/ui/guard scripts
- docs: ADR-001 (Node over Deno), dev runbook, design system rules

Co-Authored-By: Claude Fable 5.1 <[email protected]>

packages/contracts/README.md

@@ -0,0 +1,3 @@
+# @umt/contracts
+
+所有 API、SSE 事件与能力(capability)输入输出的唯一定义(zod 4 schema + 推导出的 TS 类型)。web 与 server 共用,任何一端都不得手写重复 DTO;新增接口先在这里加 schema,再由 server 用 `@hono/zod-openapi` 生成 OpenAPI。