feat(web): W3-3 site workbench, sources/feeds/snapshots, downloads with business timeline, organization records and agent sessions

- sites + /sites/:siteId: organized view with snapshot-first release list, inventory overlay,
  candidate reasons, volatile-field recheck, stale marking that keeps existing data, live search,
  unified download entry; origin view placeholder (M2)
- sources: feed CRUD/enable/fetch/reset, cursor/health/gap hints; per-site snapshot history
- tasks: download tasks with pause/resume (threshold pause cannot be bypassed), plans,
  cache volume thresholds and cleanup, business timeline (observation → plan → download →
  organization → agent/engine)
- organize: record list/detail with file-level results, manual organize with dryRun preview
- agent: session list/page and layout drawer with context prefix; streaming events,
  tool cards, rejection alerts, compaction, budget meters, model text vs server report;
  mock switch (?mock=1) until W2-D endpoints land

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/api/parse.ts

@@ -0,0 +1,39 @@
+import type { ApiErrorCode } from "@umt/contracts";
+import type { z } from "zod";
+import { ApiRequestError, apiFetch, type FetcherArg } from "~/lib/api.ts";
+
+export { ApiRequestError };
+
+/** 请求并用 contracts 的 zod schema 校验 data;失败抛 ApiRequestError(给 react-query 的 error 态) */
+export async function apiParsed<S extends z.ZodType>(schema: S, path: string, arg?: FetcherArg): Promise<z.infer<S>> {
+  const r = await apiFetch<unknown>(path, arg);
+  if (!r.ok) throw new ApiRequestError(r.error.code, r.error.message);
+  const parsed = schema.safeParse(r.data);
+  if (!parsed.success) {
+    const issue = parsed.error.issues[0];
+    throw new ApiRequestError(
+      "internal" satisfies ApiErrorCode,
+      `响应格式与合同不符:${issue ? `${issue.path.join(".")} ${issue.message}` : "未知字段"}`,
+    );
+  }
+  return parsed.data;
+}
+
+/** 变更请求:返回 data,失败抛错(给 useMutation,由 onError 统一 toast) */
+export async function apiMutate<T = unknown>(path: string, arg: FetcherArg = {}): Promise<T> {
+  const r = await apiFetch<T>(path, { method: "POST", ...arg });
+  if (!r.ok) throw new ApiRequestError(r.error.code, r.error.message);
+  return r.data;
+}
+
+export const errorCode = (err: unknown): string | null => (err instanceof ApiRequestError ? err.code : null);
+
+/** 端点是否不存在(后端尚未提供) */
+export const isMissingEndpoint = (err: unknown) => errorCode(err) === "not_found";
+
+/** 查询字符串:去掉空值 */
+export function cleanParams(p: Record<string, string | number | boolean | undefined | null>) {
+  const out: Record<string, string | number | boolean> = {};
+  for (const [k, v] of Object.entries(p)) if (v !== undefined && v !== null && v !== "") out[k] = v;
+  return out;
+}