feat: tmux 动态 resize（iPadOS 拖拽窗口/旋转自适应）

- ContentView 观测 onChange(geo.size)/onAppear → controller.containerResized
- containerResized: 点尺寸 × displayScale ÷ cell 像素 = 目标 cols×rows，去重 + debounce(200ms)
  → refresh-client -C WxH → tmux 重排回 %layout-change → 更新 pane frame
- cell 像素来自 raw 终端/pane surface metrics(InMemoryTerminalViewport.cellWidthPixels)；
  surface resize 回调只 noteCellPixels 不驱动 tmux（防反馈环，单向数据流）
- 验证：容器 1032x1280@2x cell16x35→129x73，tmux 根 rect 精确采纳，2 pane 复用不重建

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/TerminalX/iOS/ContentView.swift

@@ -167,31 +167,39 @@ struct TmuxTabChip: View {
 struct TmuxWindowView: View {
     @ObservedObject var window: TmuxWindow
     let controller: TmuxController
+    @Environment(\.displayScale) private var displayScale
 
     var body: some View {
         GeometryReader { geo in
-            if let layout = window.visibleLayout {
-                let root = layout.root.rect
-                let cw = geo.size.width / CGFloat(max(1, root.width))
-                let ch = geo.size.height / CGFloat(max(1, root.height))
-                ZStack(alignment: .topLeading) {
-                    ForEach(leaves(layout.root), id: \.pane.raw) { item in
-                        if let surface = window.panes[item.pane] {
-                            TmuxPaneView(
-                                surface: surface,
-                                isActive: window.activePane == item.pane,
-                                onTap: { controller.selectPane(item.pane, in: window.id) },
-                                onReady: { controller.markPaneReady(item.pane) }
-                            )
-                            .frame(width: CGFloat(item.rect.width) * cw,
-                                   height: CGFloat(item.rect.height) * ch)
-                            .position(x: (CGFloat(item.rect.x) + CGFloat(item.rect.width) / 2) * cw,
-                                      y: (CGFloat(item.rect.y) + CGFloat(item.rect.height) / 2) * ch)
+            Group {
+                if let layout = window.visibleLayout {
+                    let root = layout.root.rect
+                    let cw = geo.size.width / CGFloat(max(1, root.width))
+                    let ch = geo.size.height / CGFloat(max(1, root.height))
+                    ZStack(alignment: .topLeading) {
+                        ForEach(leaves(layout.root), id: \.pane.raw) { item in
+                            if let surface = window.panes[item.pane] {
+                                TmuxPaneView(
+                                    surface: surface,
+                                    isActive: window.activePane == item.pane,
+                                    onTap: { controller.selectPane(item.pane, in: window.id) },
+                                    onReady: { controller.markPaneReady(item.pane) }
+                                )
+                                .frame(width: CGFloat(item.rect.width) * cw,
+                                       height: CGFloat(item.rect.height) * ch)
+                                .position(x: (CGFloat(item.rect.x) + CGFloat(item.rect.width) / 2) * cw,
+                                          y: (CGFloat(item.rect.y) + CGFloat(item.rect.height) / 2) * ch)
+                            }
                         }
                     }
+                } else {
+                    Color.clear
                 }
-            } else {
-                Color.clear
+            }
+            // iPadOS 可自由拖拽窗口尺寸 → 容器变化即重算总格子并 refresh-client -C（controller 内 debounce）。
+            .onAppear { controller.containerResized(widthPt: geo.size.width, heightPt: geo.size.height, scale: displayScale) }
+            .onChange(of: geo.size) { _, s in
+                controller.containerResized(widthPt: s.width, heightPt: s.height, scale: displayScale)
             }
         }
     }