docs(readme): r1 复审 P2 两条措辞修正（dry-run 口径、导入取消的真实含义）

P2-1：`--dry-run` 原来写成「file list, total size, source per file」，比实现强。人类
可读输出是按角色的文件数与字节数 + 合计 + 每类一个源链样本
（crates/cli/src/commands/install/report.rs:161-201），逐文件列源是被刻意否决的设计
（crates/core/src/game/install/plan_view.rs:46-49：「只取每类的首个文件做样本……逐文件
列源选择既没用也没法读」）。整份逐文件清单只在 --json 的 data["files"] 里。

P2-2：「安装是真取消」原来挂在整合包条目下，读者会读成「整合包导入也能真停」。实际
导入取消是界面级的：面板收回 + 结果作废，后台导入跑到底（crates/presenter/src/host/
addon/pack.rs:28-42 模块文档原话「取消是界面级的……core 的 ImportRequest 没有取消
令牌」）。真取消是版本安装那条路（crates/presenter/src/host/dispatch.rs:61-88：在飞
文件就地掐断、段边界收手、不登记实例），已移到「版本管理」条目。

中英两版同步改，未动结构。

README.md

@@ -35,8 +35,11 @@ gap: the reason text is still raw Chinese straight out of the launch layer (see
   piece (`crates/app-iced/src/pages/mod.rs`, deviation #8).
 - **Version management** — a three-column rail (version type / major version / search) over the
   Mojang version list: release, snapshot and ancient versions, plus loader selection and a loader
-  version when you install. The CLI can plan the same install without downloading
-  (`ull install --dry-run`: file list, total size, source per file).
+  version when you install. Cancelling an installation really stops it — the in-flight file is cut, the
+  job ends at the next stage boundary, and no instance is registered
+  (`crates/presenter/src/host/dispatch.rs:61-88`). The CLI can plan the same install without
+  downloading (`ull install --dry-run`: per-role file counts, total size, and one source-chain sample
+  per file category; the full file list is in `--json`).
 - **Launching** — a 10-stage command-line assembly (`crates/core/src/launch/`), per-instance JVM and
   game arguments, a native-library pass, and a JSONL session record for every run. Process trees are
   killed as trees, not as one PID.
@@ -50,8 +53,9 @@ gap: the reason text is still raw Chinese straight out of the launch layer (see
 - **Loaders** — Fabric, Quilt, NeoForge and Forge. Forge/NeoForge versions that need the official
   installer `processors` really run them, with a managed JDK if the machine has none.
 - **Modpacks** — import a CurseForge manifest, a Modrinth `.mrpack`, or a MultiMC/Prism instance;
-  export as `.mrpack` or a CurseForge manifest. Installs are cancellable for real, not at the next
-  file boundary.
+  export as `.mrpack` or a CurseForge manifest. Cancelling an **import** is interface-level only: the
+  panel closes and the result is discarded, but the import thread runs to the end, because `core`'s
+  import request has no cancel token yet (`crates/presenter/src/host/addon/pack.rs:28-42`).
 - **Content library** — modpacks / mods / resource packs / shaders with keyword, source, version,
   loader and sort filters, paged results, and one-click *install into this instance*.
 - **What that page will refuse, and says so on the row** — a modpack cannot be installed *from* the