✨ feat(vscode): 「改动」面板加审查勾 + deepseek 增量生成文件改动说明

右栏 diff 头部加一组按钮:
- 审查对勾:与左树同一状态源,勾上则文件路径标题置灰
- ✨ 一键调 deepseek 生成该文件「一句话改动目的」

增量复用会话:首个文件开新 cc 会话并把 sessionId 记到
.spx/pr-file-summaries.json,后续文件 --resume 接上去,省去每次重新
理解 PR 的开销;resume 失败则丢弃旧 id 重开一次。说明也落盘(跨 push
保留),重载后仍显示。

- spawnClaude 增 resumeSessionId(--resume)
- 新增 prFileSummaryStore;handler handleGeneratePrFileSummary
  用 jsdiff 拼 unified diff 喂模型
- 依赖 diff(jsdiff)

vscode/package.json

@@ -108,6 +108,7 @@
   },
   "devDependencies": {
     "@antfu/eslint-config": "^6.7.3",
+    "@types/diff": "^8.0.0",
     "@types/node": "^25.0.3",
     "@types/vscode": "^1.97.0",
     "@vscode/vsce": "^3.9.1",
@@ -118,5 +119,8 @@
     "ovsx": "^0.10.7",
     "typescript": "^5.9.3",
     "vitest": "^4.0.16"
+  },
+  "dependencies": {
+    "diff": "^9.0.0"
   }
 }