fix: debounce pty resize and skip no-op resizes (kills duplicated TUI frames on maximize/restore)

AGENTS.md

@@ -41,3 +41,8 @@ Electron + electron-vite + React 终端工具（本地终端 / SSH / SFTP）。
 
 - 终端主题由 xterm 主题派生 UI 配色：`src/renderer/src/theme/chrome.ts` 的 `applyChromeTheme` 写入 `--chrome-bg/-bg-deep/-border/-hover` CSS 变量，antd token 在 `main.tsx` ThemedConfigProvider 派生
 - 标签强调色：`settings.tabAccentColor`（默认 `#3fb950`），经 `--tab-accent` CSS 变量生效
+
+## 终端尺寸同步
+
+- `TerminalView.scheduleFit`：fit 后**去抖 100ms** 再把 cols/rows 发给 PTY，并跳过与上次相同的尺寸。每次 ResizeObserver 都戳 PTY 会让全屏 TUI（Claude Code 等）在最大化/还原的中间尺寸上反复重绘，留下重复帧
+- 拖动窗口期间 xterm 网格立即更新，PTY 尺寸在停止后 100ms 生效

src/renderer/src/terminal/TerminalView.tsx

@@ -226,6 +226,13 @@ export const TerminalView: ForwardRefExoticComponent<TerminalViewProps & { ref?:
   const searchRef = useRef<SearchAddon | null>(null)
   const observerRef = useRef<ResizeObserver | null>(null)
   const timerRef = useRef<number>(0)
+  // PTY resize bookkeeping: `ptyTimerRef` debounces the resize while a window
+  // drag/maximize settles, `ptySizeRef` drops the no-op resizes in between.
+  // Poking the pty on every intermediate layout tick makes full-screen TUIs
+  // (Claude Code et al.) redraw repeatedly at half-settled sizes, which is what
+  // leaves duplicated frames behind in the scrollback.
+  const ptyTimerRef = useRef<number>(0)
+  const ptySizeRef = useRef<{ cols: number; rows: number } | null>(null)
   const deadRef = useRef(false)
   const searchOpenRef = useRef(false)
   const searchTermRef = useRef('')
@@ -337,9 +344,21 @@ export const TerminalView: ForwardRefExoticComponent<TerminalViewProps & { ref?:
         return
       }
       const term = termRef.current
-      if (term && !deadRef.current) {
-        window.api.resizePty(sessionId, term.cols, term.rows)
-      }
+      if (!term || deadRef.current) return
+      // The xterm grid is already correct; only tell the pty once it settles.
+      const last = ptySizeRef.current
+      if (last && last.cols === term.cols && last.rows === term.rows) return
+      window.clearTimeout(ptyTimerRef.current)
+      ptyTimerRef.current = window.setTimeout(() => {
+        const live = termRef.current
+        if (!live || deadRef.current) return
+        if (live.cols === ptySizeRef.current?.cols && live.rows === ptySizeRef.current?.rows) return
+        ptySizeRef.current = { cols: live.cols, rows: live.rows }
+        window.api.resizePty(sessionId, live.cols, live.rows)
+        // 100ms mirrors what other Electron terminals use: long enough to swallow
+        // a maximize/restore animation tick storm, short enough that a plain
+        // window drag does not visibly wrap against a stale width.
+      }, 100)
     })
   }, [sessionId])
 
@@ -616,6 +635,7 @@ export const TerminalView: ForwardRefExoticComponent<TerminalViewProps & { ref?:
     // M5: reset per-session state on (re)bind — fresh line buffer, no leftovers
     // from a template apply or panel reuse; recording resumes idle.
     lineBufRef.current = ''
+    ptySizeRef.current = null
     setSuggestions([])
     setSuggestionIndex(0)
     if (recordingRef.current) {
@@ -746,6 +766,7 @@ export const TerminalView: ForwardRefExoticComponent<TerminalViewProps & { ref?:
 
     return () => {
       if (carryTimer !== undefined) window.clearTimeout(carryTimer)
+      if (ptyTimerRef.current) window.clearTimeout(ptyTimerRef.current)
       for (const unsubscribe of unsubscribes) unsubscribe()
       for (const disposable of disposables) disposable.dispose()
       observer?.disconnect()