feat: 侧边栏新增位置兼容模式，为 Windows 原生标题栏预留顶部空间

新增 SidebarPrefs.titleBarCompat 设置项（默认关闭）：开启后 toggle cluster
下移 40px、右侧面板内容从标题栏条带下方开始，避免被 Windows 无边框窗口
右上角的原生标题栏遮挡。底部面板不受影响。设置页「常规」新增一行开关，
zh/en 双语，读写下穿既有 settings 路由。测试覆盖 parsePrefs 回退、schema
默认值、设置页渲染与开关状态。

tests/unit.spec.ts

@@ -1140,6 +1140,7 @@ describe('side card preferences', () => {
         terminalFontFamily: '',
         terminalFontSize: 13,
         interceptOpenPath: true,
+        titleBarCompat: false,
         htmlViewerNoSandbox: false,
         htmlViewerDefaultUnsafe: false,
         browserNoSandbox: false,
@@ -1164,6 +1165,7 @@ describe('side card preferences', () => {
         terminalFontFamily: '',
         terminalFontSize: 13,
         interceptOpenPath: true,
+        titleBarCompat: false,
         htmlViewerNoSandbox: false,
         htmlViewerDefaultUnsafe: false,
         browserNoSandbox: false,
@@ -1188,6 +1190,7 @@ describe('side card preferences', () => {
         terminalFontFamily: '',
         terminalFontSize: 13,
         interceptOpenPath: true,
+        titleBarCompat: false,
         htmlViewerNoSandbox: false,
         htmlViewerDefaultUnsafe: false,
         browserNoSandbox: false,
@@ -1224,6 +1227,16 @@ describe('side card preferences', () => {
     expect((await loadPrefs(wire({ interceptOpenPath: true }))).interceptOpenPath).toBe(true)
   })
 
+  it('defaults titleBarCompat to false; only an explicit true turns the position-compat mode on', async () => {
+    // Absent or malformed → off (the normal layout is the default).
+    expect((await loadPrefs(wire({}))).titleBarCompat).toBe(false)
+    expect((await loadPrefs(wire({ titleBarCompat: 'yes' }))).titleBarCompat).toBe(false)
+    expect((await loadPrefs(wire({ titleBarCompat: 1 }))).titleBarCompat).toBe(false)
+    // Explicit booleans survive verbatim.
+    expect((await loadPrefs(wire({ titleBarCompat: false }))).titleBarCompat).toBe(false)
+    expect((await loadPrefs(wire({ titleBarCompat: true }))).titleBarCompat).toBe(true)
+  })
+
   it('defaults the link-takeover protocol flags: http on, https off, master on', async () => {
     // Absent or malformed → the per-protocol defaults.
     expect((await loadPrefs(wire({}))).browserInterceptLinks).toBe(true)
@@ -1273,9 +1286,9 @@ describe('side card preferences', () => {
     const store = createSidebarStore()
     // Node environment: no window → the width falls back to PANEL_DEFAULT,
     // while the open flag still follows the preference.
-    store.setPrefs({ openByDefault: false, defaultWidthPercent: 45, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: {}, viewersEnabled: {}, pluginSettings: {} })
+    store.setPrefs({ openByDefault: false, defaultWidthPercent: 45, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, titleBarCompat: false, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: {}, viewersEnabled: {}, pluginSettings: {} })
     store.setSession('fresh-session')
-    expect(store.getPrefs()).toEqual({ openByDefault: false, defaultWidthPercent: 45, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: {}, viewersEnabled: {}, pluginSettings: {} })
+    expect(store.getPrefs()).toEqual({ openByDefault: false, defaultWidthPercent: 45, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, titleBarCompat: false, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: {}, viewersEnabled: {}, pluginSettings: {} })
     const snapshot = store.getSnapshot()
     expect(snapshot.sessionId).toBe('fresh-session')
     expect(snapshot.state?.panelOpen).toBe(false)
@@ -1311,7 +1324,7 @@ describe('side card preferences', () => {
 
   it('skips the default explorer tab when the explorer type is disabled', () => {
     const store = createSidebarStore()
-    store.setPrefs({ openByDefault: true, defaultWidthPercent: 30, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: { explorer: false }, viewersEnabled: {}, pluginSettings: {} })
+    store.setPrefs({ openByDefault: true, defaultWidthPercent: 30, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, titleBarCompat: false, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: { explorer: false }, viewersEnabled: {}, pluginSettings: {} })
     store.setSession('no-explorer')
     const state = store.getSnapshot().state!
     const tabs = allLeaves(state.splits).flatMap(leaf => leaf.tabs)
@@ -1319,7 +1332,7 @@ describe('side card preferences', () => {
     expect(state.splits.kind).toBe('leaf')
     // Re-enabling seeds the explorer tab again.
     const openStore = createSidebarStore()
-    openStore.setPrefs({ openByDefault: true, defaultWidthPercent: 30, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: {}, viewersEnabled: {}, pluginSettings: {} })
+    openStore.setPrefs({ openByDefault: true, defaultWidthPercent: 30, autoOpenSubagent: true, autoOpenJobs: true, agentTerminalTools: false, bottomPanelAutoTerminal: true, terminalFontFamily: '', terminalFontSize: 13, interceptOpenPath: true, titleBarCompat: false, htmlViewerNoSandbox: false, htmlViewerDefaultUnsafe: false, browserNoSandbox: false, browserInterceptLinks: true, browserInterceptHttp: true, browserInterceptHttps: false, tabsEnabled: {}, viewersEnabled: {}, pluginSettings: {} })
     openStore.setSession('with-explorer')
     const openTabs = allLeaves(openStore.getSnapshot().state!.splits).flatMap(leaf => leaf.tabs)
     expect(openTabs.map(tab => tab.type)).toEqual(['explorer'])