feat: merge titlebar and tab bar into single header with dynamic workspace alignment

- Merge titlebar and tab bar into a single unified top bar (.titlebar)
- Remove redundant floating workspace button that caused overlap on collapsed sidebar
- Ensure tab bar left aligns with terminal window when workspace sidebar is expanded
- Allow tab bar to sit naturally at leftmost position when workspace sidebar is collapsed
- Update test runner suite to cover merged titlebar and alignment behavior

test/test-runner.cjs

@@ -150,9 +150,9 @@ app.whenReady().then(async () => {
   `);
 
   // ==========================================
-  // Suite 2: Workspace Hierarchy & Stage Alignment
+  // Suite 2: Merged Titlebar & Workspace Alignment
   // ==========================================
-  runner.suite('2. 工作区层级结构与视口对齐验证 (UI Architecture)');
+  runner.suite('2. 顶栏与标签页栏合二为一与工作区对齐验证 (UI Architecture)');
 
   await runner.test('标题栏与工作区标识层级正确 (Titlebar Header)', async () => {
     const res = await win.webContents.executeJavaScript(`
@@ -172,50 +172,68 @@ app.whenReady().then(async () => {
     if (!res.wsName) throw new Error('Active workspace tag name is empty');
   });
 
-  await runner.test('工作区终端舞台包含独立头部标签条与视口 (.workspace-stage)', async () => {
+  await runner.test('顶栏和标签页栏合二为一 (Merged Titlebar and Tab Bar)', async () => {
     const res = await win.webContents.executeJavaScript(`
       (() => {
-        const stage = document.querySelector('.workspace-stage');
-        const header = document.querySelector('.workspace-header');
-        const viewport = document.getElementById('main-viewport');
+        const titlebar = document.querySelector('.titlebar');
+        const tabBarContainer = document.getElementById('tab-bar-container');
         const tabBar = document.getElementById('tab-bar');
         const newTabBtn = document.getElementById('btn-new-tab');
+        const viewport = document.getElementById('main-viewport');
+        const hasOldStage = !!document.querySelector('.workspace-header');
         return {
-          hasStage: !!stage,
-          hasHeader: !!header,
+          titlebarHasContainer: titlebar?.contains(tabBarContainer),
+          containerHasTabs: tabBarContainer?.contains(tabBar),
+          containerHasBtn: tabBarContainer?.contains(newTabBtn),
           hasViewport: !!viewport,
-          tabsInHeader: header?.contains(tabBar),
-          btnInHeader: header?.contains(newTabBtn),
+          hasOldHeader: hasOldStage
         };
       })()
     `);
-    if (!res.hasStage) throw new Error('Missing .workspace-stage container');
-    if (!res.hasHeader) throw new Error('Missing .workspace-header');
+    if (!res.titlebarHasContainer) throw new Error('#tab-bar-container must be inside .titlebar');
+    if (!res.containerHasTabs) throw new Error('#tab-bar must be inside #tab-bar-container');
+    if (!res.containerHasBtn) throw new Error('#btn-new-tab must be inside #tab-bar-container');
     if (!res.hasViewport) throw new Error('Missing #main-viewport');
-    if (!res.tabsInHeader) throw new Error('#tab-bar must be inside .workspace-header');
-    if (!res.btnInHeader) throw new Error('#btn-new-tab must be inside .workspace-header');
+    if (res.hasOldHeader) throw new Error('.workspace-header should be removed (merged into titlebar)');
   });
 
-  await runner.test('标签栏与终端窗口边缘完全像素级对齐 (100% Alignment)', async () => {
+  await runner.test('工作区展开时标签页和终端窗口左边像素级对齐', async () => {
     const res = await win.webContents.executeJavaScript(`
       (() => {
-        const hRect = document.querySelector('.workspace-header').getBoundingClientRect();
+        const tRect = document.getElementById('tab-bar-container').getBoundingClientRect();
         const vRect = document.getElementById('main-viewport').getBoundingClientRect();
         return {
-          headerLeft: hRect.left,
+          tabLeft: tRect.left,
           viewportLeft: vRect.left,
-          headerWidth: hRect.width,
-          viewportWidth: vRect.width,
-          leftDiff: Math.abs(hRect.left - vRect.left),
-          widthDiff: Math.abs(hRect.width - vRect.width)
+          leftDiff: Math.abs(tRect.left - vRect.left)
         };
       })()
     `);
     if (res.leftDiff >= 1) {
-      throw new Error(`Left mismatch: header.left=${res.headerLeft}, viewport.left=${res.viewportLeft}`);
+      throw new Error(`Left mismatch: tabLeft=${res.tabLeft}, viewportLeft=${res.viewportLeft}`);
     }
-    if (res.widthDiff >= 1) {
-      throw new Error(`Width mismatch: header.width=${res.headerWidth}, viewport.width=${res.viewportWidth}`);
+  });
+
+  await runner.test('工作区关闭时标签页位于左侧且不强求与终端左边对齐', async () => {
+    const res = await win.webContents.executeJavaScript(`
+      (() => {
+        // 折叠侧边栏
+        window.terminalApp?.workspaceManager?.setCollapsed(true);
+        const tRect = document.getElementById('tab-bar-container').getBoundingClientRect();
+        const titlebarLeft = document.getElementById('titlebar-left').getBoundingClientRect();
+        const vRect = document.getElementById('main-viewport').getBoundingClientRect();
+        // 恢复展开状态供后续测试
+        window.terminalApp?.workspaceManager?.setCollapsed(false);
+        return {
+          tabLeft: tRect.left,
+          controlsRight: titlebarLeft.right,
+          viewportLeft: vRect.left,
+          distFromControls: Math.abs(tRect.left - titlebarLeft.right)
+        };
+      })()
+    `);
+    if (res.distFromControls >= 2) {
+      throw new Error(`Tab bar not immediately beside titlebar-left controls when collapsed: tabLeft=${res.tabLeft}, controlsRight=${res.controlsRight}`);
     }
   });