feat(downloads): fold download plans into download panel (DL-3)

- Waiting plans (approval / disk space / automation off / queued) are
  active-segment rows on /download-tasks/board, merged by created_at,
  counted, with approve / cancel actions; ?plan= deep links and legacy
  /downloads/plans routes redirect to the panel
- Download detail shows "why this download" (source, purpose, replaced
  version, reasons); raw evaluation in tech info
- Failed / cancelled / expired plans appear in the entity download
  history; rejected / revoked / expired approvals close draft plans
- New GET /acquisition-plans/{id}/why, POST /acquisition-plans/{id}/cancel
- User-facing copy no longer says 下载计划; glossary updated

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

packages/contracts/src/capability.ts

@@ -177,8 +177,8 @@ export const CAPABILITY_CATALOG: Record<KnownCapabilityId, CapabilityDescriptor>
   ),
   "download.plan": d(
     "download.plan",
-    "生成下载计划",
-    "评估候选，生成占用收录版本(slot)与预算预留的下载计划；不提交。选定资源后、提交前用；不会提交下载，也不预留收录版本",
+    "准备下载",
+    "评估选定的资源能否下到这个收录版本(slot)，准备一份待提交的下载（返回 planId）；不提交，也不占用收录版本与预算。选定资源后、提交前用",
     "preview",
     "DownloadPlan",
     "organize.execute",
@@ -189,7 +189,7 @@ export const CAPABILITY_CATALOG: Record<KnownCapabilityId, CapabilityDescriptor>
   "download.submit": d(
     "download.submit",
     "提交下载",
-    "按已保存的计划提交到下载器；校验授权与硬阈值。只提交 download.plan 生成的计划；结果未知时先用 download.inspect / task.inspect 核对，不要重复提交",
+    "把 download.plan 准备好的下载（planId）提交到下载器；校验授权与硬阈值。只提交 download.plan 返回的 planId；结果未知时先用 download.inspect / task.inspect 核对，不要重复提交",
     "execute",
     "DownloadSubmit",
     "organize.execute",
@@ -602,6 +602,8 @@ export interface CapabilityActivity {
   noun: string;
   unit: string | null;
   hidden?: boolean;
+  /** 动作后不加「了」(「准备下载 1 个资源」) */
+  bare?: boolean;
 }
 
 const act = (verb: string, noun: string, unit: string | null = null): CapabilityActivity => ({ verb, noun, unit });
@@ -611,7 +613,7 @@ export const CAPABILITY_ACTIVITY: Record<KnownCapabilityId, CapabilityActivity>
   "release.search": act("搜", "资源", "次"),
   "release.inspect": act("看", "资源", "个"),
   "identity.resolve": act("识别", "作品", "个"),
-  "download.plan": act("生成", "下载计划", "份"),
+  "download.plan": { ...act("准备下载", "资源", "个"), bare: true },
   "download.submit": act("提交", "下载", "个"),
   "download.recheck": act("校验", "下载任务", "个"),
   "organize.plan": act("生成", "整理计划", "份"),