fix(downloads): humanized reasons and TechInfo on the download panel (DL-2b)

- board organize hint uses DEAI-2 reasonLine; add transfer_failed, blocked,
  blocked_by_conflict, main_failed, not_imported_kind, target_root_not_managed,
  download_removed to the reason table with tests
- download detail / plans tab: internal ids, raw codes and JSON moved into TechInfo
- library versions tech block switched to TechInfo (TODO(DEAI-2))
- copy: glossary terms (no 接管/候选), plan reason codes no longer shown raw

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

packages/contracts/test/reasons.test.ts

@@ -10,6 +10,14 @@ describe("reasonText(DEAI-2 原因码人话化)", () => {
     expect(reasonText("below_min_size")?.text).toContain("最小体积");
   });
 
+  it("下载面板用到的码(DL-2b):整理失败、冲突、下载被删", () => {
+    expect(reasonSentence("transfer_failed")).toBe("文件没有整理成功。在整理记录里查看失败的文件");
+    expect(reasonSentence("blocked")).toBe("有冲突要先处理。去待处理");
+    expect(reasonText("download_removed")?.text).toBe("下载任务已从下载器删除");
+    expect(reasonText("target_root_not_managed")?.text).toContain("本工具管理");
+    for (const c of ["blocked_by_conflict", "main_failed", "not_imported_kind"]) expect(reasonText(c)).not.toBeNull();
+  });
+
   it("不认识的码返回 null;句子兜底不把码原样给人看", () => {
     expect(reasonText("some_new_code")).toBeNull();
     expect(reasonSentence("some_new_code")).toBe("处理失败");