fix(terminal): 左侧/底部侧栏拖动改用工作区根元素的真实 bounds

侧栏拖动的宽度换算依赖 workspace_bounds,而它此前由
WorkspaceResizeEventHandler::prepaint 用元素自身 bounds 写入。该元素是
h_flex 里 0×0 的弹性子项,落在工作区右缘、垂直居中,于是:

- 左侧:`鼠标 x - 工作区右缘` 恒为负,每次拖动都被夹到最小宽度
  (280),表现为「移到左边后拖不动」。
- 底部:`工作区中线 - 鼠标 y` 同样为负,也被夹到最小宽度。
- 右侧:元素右缘恰好等于工作区右缘,才碰巧正常。

改为在工作区根 h_flex 上用 on_prepaint 捕获真实 bounds(与 db_view 的
写法一致),事件处理元素只保留鼠标监听。内嵌 dock(TerminalView 嵌入
资源工作台)的 view_bounds 同样从 window.bounds() 改为 dock 根元素的
on_prepaint,避免视图不在窗口原点时换算偏移。

新增两条契约测试分别锁定工作区与内嵌 dock 的 bounds 来源。

验证:cargo test -p terminal_view --lib 572 passed。

crates/terminal_view/src/view/render_layout.rs

@@ -88,6 +88,7 @@ impl TerminalView {
     ) -> AnyElement {
         let state = self.tool_dock_render_state(cx);
         let view = cx.entity().clone();
+        let bounds_view = view.clone();
         let bg_color = self.current_theme.background;
         let center = CenterRegionState {
             font_family,
@@ -106,6 +107,13 @@ impl TerminalView {
             .min_w_0()
             .min_h_0()
             .overflow_hidden()
+            // 拖动换算要用 dock 根元素的真实 bounds;事件监听元素自身是 0×0,
+            // 而 window.bounds() 在嵌入面板里也不等于 dock 的位置。
+            .on_prepaint(move |bounds, _, cx| {
+                bounds_view.update(cx, |view, _| {
+                    view.view_bounds = bounds;
+                });
+            })
             .bg(bg_color)
             .key_context(TERMINAL_CONTEXT)
             .on_action(cx.listener(Self::start_recording_action))

crates/terminal_view/src/view/resize_event_handler.rs

@@ -40,16 +40,11 @@ impl Element for ResizeEventHandler {
         _: Option<&InspectorElementId>,
         _: Bounds<Pixels>,
         _: &mut Self::RequestLayoutState,
-        window: &mut Window,
-        cx: &mut App,
+        _window: &mut Window,
+        _cx: &mut App,
     ) -> Self::PrepaintState {
-        let bounds = window.bounds();
-        self.view.update(cx, |view, _| {
-            view.view_bounds = Bounds {
-                origin: Point::default(),
-                size: bounds.size,
-            };
-        });
+        // view_bounds 由 dock 根元素的 on_prepaint 写入:本元素是 0×0 的弹性
+        // 子项,而窗口 bounds 在嵌入面板里也不等于 dock 的位置。
     }
 
     fn paint(

crates/terminal_view/src/view/tests/layout.rs

@@ -945,3 +945,24 @@ fn terminal_render_uses_cached_font_metrics() {
     assert!(metric_source.contains("fn refresh_terminal_font_metrics("));
     assert!(!render_setup.contains("cx.text_system().all_font_names()"));
 }
+
+/// 内嵌 dock 的拖动换算同样必须使用 dock 根元素的真实 bounds,
+/// 不能用 `window.bounds()`(嵌入面板时原点/尺寸都不是 dock 的)。
+#[test]
+fn embedded_sidebar_resize_uses_dock_bounds_not_window_bounds() {
+    let render_layout = include_str!("../render_layout.rs");
+    let resize_event_handler = include_str!("../resize_event_handler.rs");
+
+    assert!(
+        render_layout.contains(".on_prepaint(move |bounds, _, cx|"),
+        "tool dock root must capture its own bounds via on_prepaint"
+    );
+    assert!(
+        render_layout.contains("view.view_bounds = bounds"),
+        "tool dock root prepaint must write view_bounds"
+    );
+    assert!(
+        !resize_event_handler.contains("window.bounds()"),
+        "resize event handler must not derive view bounds from the window"
+    );
+}

crates/terminal_view/src/workspace/layout.rs

@@ -3,7 +3,7 @@ use gpui::{
     AnyElement, Context, InteractiveElement as _, IntoElement as _, ParentElement as _,
     Styled as _, div,
 };
-use gpui_component::{h_flex, v_flex};
+use gpui_component::{ElementExt as _, h_flex, v_flex};
 use one_core::layout::TOOLBAR_WIDTH;
 use one_core::sidebar_contribution::SidebarPlacement;
 
@@ -76,12 +76,21 @@ impl TerminalWorkspace {
                 )
             });
 
+        let workspace = cx.entity();
         h_flex()
             .id("terminal-workspace-root")
             .size_full()
             .min_w_0()
             .min_h_0()
             .overflow_hidden()
+            // 侧栏拖动换算要用工作区根元素的真实 bounds。事件监听元素本身是
+            // 0×0 的弹性子项,拿它自己的 bounds 当工作区边界会让左/下拖动
+            // 永远被夹到最小宽度。
+            .on_prepaint(move |bounds, _, cx| {
+                workspace.update(cx, |workspace, _| {
+                    workspace.workspace_bounds = bounds;
+                });
+            })
             .when_some(left, |this, panel| {
                 this.child(
                     div()

crates/terminal_view/src/workspace/resize.rs

@@ -116,14 +116,13 @@ impl Element for WorkspaceResizeEventHandler {
         &mut self,
         _: Option<&GlobalElementId>,
         _: Option<&InspectorElementId>,
-        bounds: Bounds<Pixels>,
+        _: Bounds<Pixels>,
         _: &mut Self::RequestLayoutState,
         _: &mut Window,
-        cx: &mut App,
+        _: &mut App,
     ) -> Self::PrepaintState {
-        self.workspace.update(cx, |workspace, _| {
-            workspace.workspace_bounds = bounds;
-        });
+        // 工作区 bounds 由根元素的 on_prepaint 写入:本元素是 0×0 的弹性
+        // 子项,自身 bounds 不能当作工作区边界。
     }
 
     fn paint(

crates/terminal_view/src/workspace/tests.rs

@@ -198,3 +198,25 @@ fn closing_pane_preserves_surviving_ratio(cx: &mut TestAppContext) {
     assert_width(pane_width(visual, PANE_SELECTORS[1]), px(630.));
     assert_eq!(2, visual.read(|cx| harness.read(cx).tree.panes().len()));
 }
+
+/// 侧栏拖动换算依赖 `workspace_bounds`。它必须来自工作区根元素的真实
+/// bounds:事件监听元素是 0×0 的弹性子项,拿它自己的 bounds 会让左侧
+/// 与底部拖动永远被夹到最小宽度(左侧面板拖不动)。
+#[test]
+fn sidebar_resize_bounds_come_from_the_workspace_root() {
+    let layout_source = include_str!("layout.rs");
+    let resize_source = include_str!("resize.rs");
+
+    assert!(
+        layout_source.contains(".on_prepaint(move |bounds, _, cx|"),
+        "workspace root must capture its own bounds via on_prepaint"
+    );
+    assert!(
+        layout_source.contains("workspace.workspace_bounds = bounds"),
+        "workspace root prepaint must write workspace_bounds"
+    );
+    assert!(
+        !resize_source.contains("workspace_bounds = bounds"),
+        "resize event handler is zero-sized; its bounds must not be used as the workspace bounds"
+    );
+}