fix: 处理 Copilot 二轮 review 的 10 条评论

- BrowserView: 即使 host 在白名单，GUI 自身 origin 永不给 allow-same-origin（裸 host 条目覆盖所有端口时可提权）
- intercept: revealInExplorer 相对路径经 resolveSidebarPath 解析后再 revealPaths（交付物路径是相对的）
- intercept: ctx.betterSidebar 改为 ctx.get（#357 纤维链读取约定）
- FileTree/EditorHost/TreePanel/tabs: 把 revealed 贯通到树行渲染 + 高亮类 + scrollIntoView（此前高亮永不渲染）
- state.revealPaths: 重建祖先目录时保留前导分隔符（POSIX/UNC 此前目录永远折叠）
- state.schedulePersist: 仅活动会话写入全局宽度（targeted open 不再用非活动会话的过期宽度覆盖拖拽值）
- browser.probe: GET 回退显式取消 body（否则流式/大响应挂住 socket）
- terminal-font: leading generic 前只放 symbols-only 字体；fully-patched 放 generic 后（避免 hijack 度量字体）
- sidebar.module.css: 恢复拖拽反馈（#130 的 silent resize 与 PR 描述冲突，取 HEAD）
- Sidebar: 剩余 4 处 ctx.betterSidebar 改 ctx.get
- tests: 补 revealPaths/iframeSandboxFor/terminal-font 回归测试 + EditorHost/FileTree 测试补 revealed prop

src/client/state.ts

@@ -730,8 +730,13 @@ export function revealPaths(state: SidebarState, cwd: string | undefined, files:
     revealed.push(file)
     const parts = file.split(/[\\/]+/).filter(part => part !== '' && part !== '.')
     const separator = file.includes('\\') ? '\\' : '/'
+    // Keep the original leading separator(s) when rebuilding ancestor dirs:
+    // FileTree matches expansion against ABSOLUTE paths, so dropping the
+    // root (POSIX `/w/src` �W `w/src`) or a UNC prefix (`\\server\share`)
+    // would leave every ancestor collapsed and the row unreachable.
+    const prefix = file.startsWith('/') ? '/' : file.startsWith('\\\\') ? '\\\\' : file.startsWith('\\') ? '\\' : ''
     for (let i = rootParts.length; i < parts.length - 1; i++) {
-      expanded.add(parts.slice(0, i + 1).join(separator))
+      expanded.add(prefix + parts.slice(0, i + 1).join(separator))
     }
   }
   if (revealed.length === 0) return state
@@ -1454,8 +1459,13 @@ export class SidebarStore {
 
   private schedulePersist(sessionId: string, state: SidebarState): void {
     // Keep the cross-session width in sync: any width change (drag, fullscreen
-    // toggle) becomes the shared width for every conversation.
-    writeGlobalWidth(state.width)
+    // toggle) on the ACTIVE session becomes the shared width for every
+    // conversation. A targeted open persists an INACTIVE session (reduceFor)
+    // and must not clobber that global — its width is stale by definition,
+    // so writing it would break "last drag wins".
+    if (sessionId === this.snapshot.sessionId) {
+      writeGlobalWidth(state.width)
+    }
     // Per-session debounce timers: one session's pending write must never
     // cancel another's (targeted opens schedule writes for INACTIVE
     // sessions while the active session may already have one pending —