chore(baseline): target DSH 0.1.6-alpha.2 and drop 0.1.5-rc support

The peer floor had to move: semver's prerelease rule needs a comparator on the
same [major,minor,patch] tuple, so `^0.1.5-rc.1` can never match any 0.1.6
prerelease. The floor becomes `^0.1.6-alpha.2` (which does admit 0.1.6 alpha/rc
prereleases and excludes 0.1.5), and `engines.dsh` follows. This is a deliberate
support-line break, matching how v0.19.0 dropped 0.1.2: 0.1.5-rc hosts stay on
0.19.1.

Three upstream changes actually reach this plugin and are adapted here:

- `IconSendOutline16` no longer exists in ui-primitives (only
  `IconSendOutline14`).
- `TerminalBlockLabels` gained a required `noExitCode` pill text.
- `ConnectionIndicator` dropped `reconnectLabel`: the outage label is now the
  one static label that already names the retry action, so the label copy moves
  there, matching the host's own '连接异常，点击立即重连'.

ui-primitives still declares no `dependencies` while its bundle bare-imports
more than it used to: `diff` and `simple-icons` were previously satisfied only
transitively and had to be hoisted into devDependencies, exactly like the
anser/shiki/katex group before them. `@deepseek-ai/dsh-code-runtime` is gone
upstream (the package no longer exists) and leaves the dev tree.

The e2e fallback npx spec is pinned rather than version-less: an unpinned
`npx @deepseek-ai/dsh` resolves npm's `latest`, which is still the 0.1.5 line
this plugin no longer supports.

scripts/e2e-common.sh

@@ -40,11 +40,16 @@ e2e_require_cmd() {
 # ── DSH_CMD 解析 ─────────────────────────────────────────────────────────────
 # PATH 上的 dsh 优先，否则 npx 拉官方包（同 scripts/install.sh）。DSH_CMD
 # 缺省值（`dsh`）由调用方从环境变量取好传入。
+#
+# 回退的 npx 版本是显式钉死的：不钉就会解析 npm 的 `latest` dist-tag，而
+# 0.1.6 线目前只有预发布（`latest` 仍是 0.1.5-rc.2），冒烟会静静地挂到一
+# 个插件已不支持的宿主上。钉版必须与 package.json 的 peer 下限同步。
+DSH_NPX_SPEC="${DSH_NPX_SPEC:-@deepseek-ai/dsh@0.1.6-alpha.2}"
 e2e_resolve_dsh_cmd() {
   if ! command -v "$DSH_CMD" >/dev/null 2>&1; then
     if command -v npx >/dev/null 2>&1; then
-      say "PATH 上无 ${DSH_CMD}，回退 npx -y --package @deepseek-ai/dsh"
-      DSH_CMD="npx -y --package @deepseek-ai/dsh dsh"
+      say "PATH 上无 ${DSH_CMD}，回退 npx -y --package ${DSH_NPX_SPEC}"
+      DSH_CMD="npx -y --package ${DSH_NPX_SPEC} dsh"
     else
       die "未找到 $DSH_CMD 或 npx；请先安装 DSH CLI（npm i -g @deepseek-ai/dsh）或用 DSH_CMD 指定"
     fi