✨ feat(vscode): profile 值编辑器改为多行+图片粘贴（图片落 .spx/profile-assets）

双击 profile 值单元格改为打开富编辑弹窗：多行 textarea + Ctrl+V 粘贴截图，
⌘/Ctrl+Enter 或点遮罩保存、Esc 取消。值仍是单个字符串，图片存磁盘
（内容寻址 sha1 命名，去重），值里只留 markdown 引用，不撑大 profiles.json。
折叠单元格显示首行 + 含图时加 🖼 徽标。key/列头仍走原内联输入。

- 抽公用 lib/imagePaste：同步探测(preventDefault) + 异步读取，新建工单改用它、行为不变
- 新增扩展侧 profileAssets handler：存图(image/* 校验)/读图(挡路径穿越)
- 新增 useProfileAssets(requestId 关联并发) 与 ProfileCellEditor 弹窗
- 消息两侧同步 profile-asset/save|load|saved|loaded

vscode/src/panel/KanbanPanel.ts

@@ -27,6 +27,7 @@ import { loadYouTrackIssues } from '../youtrack/issueLoader'
 import * as issues from './handlers/issues'
 import * as managedSessions from './handlers/managedSessions'
 import * as prFiles from './handlers/prFiles'
+import * as profileAssets from './handlers/profileAssets'
 import * as sessions from './handlers/sessions'
 import * as settings from './handlers/settings'
 import * as terminals from './handlers/terminals'
@@ -378,6 +379,14 @@ export class KanbanWebviewPanel {
       void settings.handleProfilesList(this)
       return
     }
+    if (msg.type === 'profile-asset/save') {
+      void profileAssets.handleSaveProfileAsset(this, msg)
+      return
+    }
+    if (msg.type === 'profile-asset/load') {
+      void profileAssets.handleLoadProfileAsset(this, msg)
+      return
+    }
     if (msg.type === 'toast/open-url') {
       void env.openExternal(Uri.parse(msg.url))
       return