fix(test): add missing devDeps + sourcemap transform + jsdom directives

WorkBuddy review found 38 of 131 spec files failed at collection time
(0 tests executed) — the '1015 passed' was a false green because vitest
only counts 'Tests failed', not 'Test Files failed'.

Root cause: dsh-client-ui-primitives@0.2.0-rc.2 declares dependencies:null
but statically imports 23 external root packages. Our project declared
only 18. Under pnpm strict layout, the missing 5 (dsh-client-store,
dsh-util-code-language, dsh-util-workspace-path, diff, simple-icons)
were unresolvable when Vite inlined the primitives package.

Fixes:
- Add 7 missing devDeps: dsh-client-store@0.2.0-rc.2,
  dsh-util-code-language@0.2.0-rc.2, dsh-util-workspace-path@0.2.0-rc.2,
  diff@9.0.0, simple-icons@16.35.0, zustand@5.0.15, immer@11.1.21
- vitest.config.ts: add transform plugin to strip sourceMappingURL
  comments from dsh-client-ui-primitives (upstream ships lib/index.js
  with trailing sourceMappingURL but package.json files excludes .map)
- 5 spec files: add @vitest-environment jsdom directive (they import
  dsh-client-ui-primitives which calls window.addEventListener at module
  load; node environment lacks window)
- Remove empty .map file hack from node_modules (ineffective + .gitignore
  blocks it from version control)

Result: Test Files 131 passed (131), Tests 1367 passed | 9 skipped,
EXIT=0.

Verified: simple-icons 25 named exports all present.
Typecheck + build pass.

package.json

@@ -159,6 +159,7 @@
     "@deepseek-ai/dsh-agent-loop": "0.2.0-rc.2",
     "@deepseek-ai/dsh-attachment": "0.2.0-rc.2",
     "@deepseek-ai/dsh-client-locale": "0.2.0-rc.2",
+    "@deepseek-ai/dsh-client-store": "0.2.0-rc.2",
     "@deepseek-ai/dsh-client-ui-conversation": "0.2.0-rc.2",
     "@deepseek-ai/dsh-client-ui-primitives": "0.2.0-rc.2",
     "@deepseek-ai/dsh-client-ui-settings": "0.2.0-rc.2",
@@ -177,7 +178,9 @@
     "@deepseek-ai/dsh-system-prompt": "0.2.0-rc.2",
     "@deepseek-ai/dsh-tools": "0.2.0-rc.2",
     "@deepseek-ai/dsh-user-approval": "0.2.0-rc.2",
+    "@deepseek-ai/dsh-util-code-language": "0.2.0-rc.2",
     "@deepseek-ai/dsh-util-time": "0.2.0-rc.2",
+    "@deepseek-ai/dsh-util-workspace-path": "0.2.0-rc.2",
     "@eslint/js": "^10.0.1",
     "@huanlin/dsh-plugin-better-locale": "^0.1.0",
     "@playwright/test": "^1.62.1",
@@ -191,9 +194,11 @@
     "@xterm/xterm": "^5.5.0",
     "anser": "^2.3.5",
     "cordis": "^4.0.0-rc.8",
+    "diff": "9.0.0",
     "eslint": "^10.9.1",
     "eslint-plugin-react-hooks": "^7.1.1",
     "globals": "^17.12.0",
+    "immer": "11.1.21",
     "jsdom": "^29.1.1",
     "katex": "^0.16.47",
     "lightningcss": "^1.32.0",
@@ -212,11 +217,13 @@
     "react": "^18.2.0",
     "react-dom": "18.2.0",
     "shiki": "^4.3.1",
+    "simple-icons": "16.35.0",
     "tsdown": "^0.22.2",
     "typescript": "^5.6.0",
     "typescript-eslint": "^8.69.0",
     "unrun": "^0.2.39",
-    "vitest": "^4.1.8"
+    "vitest": "^4.1.8",
+    "zustand": "5.0.15"
   },
   "forkedFrom": {
     "name": "dsh-better-sidebar",