feat(ui): 自由窗口——tab 拖出侧边栏成为可移动/缩放/置顶的浮动窗口 (v0.16.0)

- 拖出：标签栏 tab 拖到主会话列（HTML5 DnD 检测 + 虚线提示浮层）或右键菜单
  「移动到自由窗口」（右/底面板共用 TabBar），tab 从 pane 移动进 SidebarState.floats
- 窗口（FreeWindow，渲染于 [data-dsh-panel-host] z-42）：头部 pointer 拖动
  （rAF 直写 + 松手提交）、拖到 pane 高亮停靠（center 合并）、SE 角缩放、
  点击置顶、头部右键（回到侧边栏/关闭）、X = closeTab 走正常生命周期
- 服务语义：openTab dedupe/id 聚焦浮动 tab = 置顶窗口（不展开面板）；
  closeTab/activateTab 兼顾 floats；agent 终端 reconcile 覆盖浮窗；
  features 单调新增 'floatWindows'，版本 0.16.0
- 持久化：floats 随会话 localStorage，sanitizeState 宽容校验 + 几何钳制，
  uid 播种覆盖 float 前缀；i18n 三键 19 语言同步
- 关键修复（e2e 发现）：portal 覆盖层（头部 Menu）的合成事件沿 React 树
  冒泡回拖拽表面，劫持菜单行点击——拖拽起点加 DOM 同源守卫（jsdom 不复现）
- e2e-mount.sh：缺省 tarball 改取 mtime 最新（旧字典序选择会把冒烟挂到
  过期产物）；新增 tests/e2e/float-window.e2e.ts 双用例

src/client/service.ts

@@ -22,8 +22,8 @@
 import type { ReactNode } from 'react'
 import type { Context } from '../context-types.ts'
 import {
-  activateTab as activateTabReducer, allLeaves, closeTab as closeTabReducer, leafWithTab,
-  openTabInActivePane, patchTab, tabOpenIn, togglePanel, treeOf,
+  activateTab as activateTabReducer, allLeaves, closeTab as closeTabReducer, closeFloatByTab, floatWithTab,
+  leafWithTab, openTabInActivePane, patchTab, raiseFloat, tabOpenIn, togglePanel, treeOf,
   type SidebarSnapshot, type SidebarState, type SidebarStore, type SidebarTab,
 } from './state.ts'
 import { isNarrowWidth } from './breakpoints.ts'
@@ -470,7 +470,7 @@ export function matchUrlTarget(tabs: readonly TabDescriptor[], url: URL): TabDes
  * The plugin version this service instance reports. Keep in lockstep with
  * `package.json`'s version — `tests/service.spec.ts` asserts the pair.
  */
-export const SIDEBAR_SERVICE_VERSION = '0.15.2'
+export const SIDEBAR_SERVICE_VERSION = '0.16.0'
 
 /**
  * Monotonic capability list consumers use to gate new API usage (features
@@ -485,6 +485,9 @@ export const SIDEBAR_SERVICE_VERSION = '0.15.2'
  * - 'pluginSettings': SidebarSettingsDeclaration.pluginToggles/render
  * - 'urlTarget' (v0.13.0): TabDescriptor.urlTarget (external-link claims)
  * - 'settingSelect': SidebarSettingToggle type 'select' (options/multi)
+ * - 'floatWindows' (v0.16.0): tabs float as free windows — openTab's dedupe/
+ *   id focus targets RAISE the floating window (never duplicate the tab or
+ *   expand panels), closeTab on a floating tab closes it with its window.
  */
 export const SIDEBAR_FEATURES = [
   'badge',
@@ -497,6 +500,7 @@ export const SIDEBAR_FEATURES = [
   'pluginSettings',
   'urlTarget',
   'settingSelect',
+  'floatWindows',
 ] as const
 
 /** Run one plugin callback; a throw is logged and never breaks the caller. */
@@ -651,6 +655,7 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
       const dedupeKey = descriptor.dedupeKey ?? (descriptor.single === true ? () => descriptor.id : undefined)
       const key = dedupeKey?.(tab)
       const inputTabs = allLeaves(state.splits).concat(allLeaves(state.bottomSplits)).flatMap(leaf => leaf.tabs)
+        .concat(state.floats.map(f => f.tab))
       const existedByKey = key !== undefined
         && inputTabs.some(candidate => candidate.type === tab.type && dedupeKey!(candidate) === key)
       const existedById = tabOpenIn(state, tab.id)
@@ -675,12 +680,24 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
       } else {
         // A focus happened: resolve the tab that is actually active now and
         // report THAT to onActivate (never the caller's un-inserted seed).
+        // The pool covers free windows too — a floating instance focuses by
+        // raising, and the callback must see the real (patched) tab.
         const candidates = allLeaves(landed.splits).concat(allLeaves(landed.bottomSplits)).flatMap(leaf => leaf.tabs)
+          .concat(landed.floats.map(f => f.tab))
         activated = key !== undefined
           ? candidates.find(candidate => candidate.type === tab.type && dedupeKey!(candidate) === key)
           : candidates.find(candidate => candidate.id === tab.id)
         activated ??= tab
       }
+      // A CONTENT open that focuses an existing FLOATING tab is already in
+      // sight (free windows render regardless of panel state): expanding a
+      // panel for it would point the user at a pane the content is not in.
+      if (
+        !isCreation
+        && floatWithTab(landed, activated?.id ?? tab.id) !== undefined
+      ) {
+        return landed
+      }
       // A CONTENT open (file / browser) must land in sight: when the panel
       // hosting the landing pane is collapsed, expand it. On narrow
       // viewports the two workbenches merge into one drawer, so the drawer
@@ -728,6 +745,12 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
       // Unknown tab ids are a strict no-op: no state churn, no notify, no
       // pointless localStorage rewrite (mirrors updateTab's short-circuit).
       if (!tabOpenIn(state, tabId)) return state
+      // A floating tab closes WITH its window — the float is the tab's pane.
+      const float = floatWithTab(state, tabId)
+      if (float !== undefined) {
+        closed = float.tab
+        return closeFloatByTab(state, tabId)
+      }
       const paneId = findPaneIdOf(state, tabId)
       const leaf = leafWithTab(state[treeOf(state, paneId)], tabId)
       closed = leaf?.tabs.find(tab => tab.id === tabId)
@@ -764,6 +787,12 @@ export function createBetterSidebarService(store: SidebarStore): BetterSidebarSe
     store.reduce((state) => {
       // Unknown tab ids are a strict no-op (no state churn / notify).
       if (!tabOpenIn(state, tabId)) return state
+      // A floating tab "activates" by raising its window — no pane switch.
+      const float = floatWithTab(state, tabId)
+      if (float !== undefined) {
+        activated = float.tab
+        return raiseFloat(state, float.id)
+      }
       const paneId = findPaneIdOf(state, tabId)
       const leaf = leafWithTab(state[treeOf(state, paneId)], tabId)
       activated = leaf?.tabs.find(tab => tab.id === tabId)
@@ -825,6 +854,10 @@ function applyDedupe(state: SidebarState, tab: SidebarTab, descriptor: TabDescri
       const existing = leaf.tabs.find(t => t.type === tab.type && dedupeKey!(t) === key)
       if (existing !== undefined) return activateTabReducer(state, leaf.id, existing.id)
     }
+    // A floating instance focuses by raising its window (no duplicate tab,
+    // no panel expansion — the window is the tab's pane).
+    const floated = state.floats.find(f => f.tab.type === tab.type && dedupeKey!(f.tab) === key)
+    if (floated !== undefined) return raiseFloat(state, floated.id)
   }
   return openTabInActivePane(state, tab)
 }