feat: 独立镜像桥（免 DSH 重启出镜像/指标）+ 去掉 IP 显示 + 上下文占比兜底

- tools/mirror-bridge.mjs：直接读 %DSH_HOME%/sessions/**/session.jsonl.zstd（多帧 zstd 按魔数切帧解）
  与 storages/session_projcache.json，算出 消息行/轮/步/tok·s⁻¹/token/上下文占比 并写
  snapshot-bridge.json（插件缺字段时由浮窗补齐）；插件在写 snapshot.json 时它不抢
- 浮窗标题栏不再显示 endpoint IP，只在未连接时显示状态词；数据来自桥时指标带 ≈
- host: contextUsed 兜底按 1M 上下文算（真机 sessionProjection=n，拿不到上下文窗口）
- 实测：snapshot -> page rows=40 turns=1 steps=67 tok=214639；outbox watch 切会话生效

shell/float-window.ps1

@@ -69,7 +69,11 @@ $commandFile = Join-Path $stateDir 'command.json'
 $aliveFile = Join-Path $stateDir 'alive.json'
 # 文件桥：插件每秒写 snapshot.json（桌面壳 HTTP 网关 403，浮窗只能走文件）
 $snapshotFile = Join-Path $DshHome 'float-window\snapshot.json'
+$bridgeSnapshotFile = Join-Path $DshHome 'float-window\snapshot-bridge.json'
 $outboxFile = Join-Path $DshHome 'float-window\outbox.json'
+$watchFile = Join-Path $DshHome 'float-window\watch.json'
+# 独立镜像桥：直接读会话日志/投影缓存（DSH 还没重启、插件没在写快照时的兜底数据源）
+$bridgeScript = Join-Path (Split-Path $PSScriptRoot -Parent) 'tools\mirror-bridge.mjs'
 if ($alreadyRunning) {
     if ($Action) {
         try {
@@ -387,7 +391,13 @@ $onWebMessage = {
         'scale'      { $script:state.scale = [double]$m.value; $wv.ZoomFactor = [double]$m.value; Save-State; Push-State }
         'reload'     { $wv.Reload() }
         'chat'       { Write-Outbox @{ cmd = 'chat'; text = [string]$m.text } }
-        'watch'      { Write-Outbox @{ cmd = 'watch'; sessionId = [string]$m.sessionId } }
+        'watch'      {
+            Write-Outbox @{ cmd = 'watch'; sessionId = [string]$m.sessionId }
+            # 镜像桥也跟随同一个选择
+            try {
+                [System.IO.File]::WriteAllText($watchFile, (@{ sessionId = [string]$m.sessionId } | ConvertTo-Json -Compress), (New-Object System.Text.UTF8Encoding($false)))
+            } catch { }
+        }
         'newSession' { Write-Outbox @{ cmd = 'session'; action = 'create' } }
         'openExternal' { if ($m.url -match '^https?://') { Start-Process $m.url } }
     }
@@ -427,7 +437,28 @@ $timer.Add_Tick({
                 $s = [System.IO.File]::ReadAllText($snapshotFile, [System.Text.Encoding]::UTF8)
                 if ($s -and $s -ne $script:lastSnapshotText) {
                     $script:lastSnapshotText = $s
-                    Send-ToPage @{ type = 'snapshot'; data = ($s | ConvertFrom-Json) }
+                    $snap = $s | ConvertFrom-Json
+                    # 用镜像桥的兜底快照补齐插件缺的字段（token/上下文估算、标题）
+                    try {
+                        if (Test-Path $bridgeSnapshotFile) {
+                            $bs = [System.IO.File]::ReadAllText($bridgeSnapshotFile, [System.Text.Encoding]::UTF8) | ConvertFrom-Json
+                            if ($bs -and $bs.sessionId -eq $snap.sessionId) {
+                                if ($null -eq $snap.metrics.contextUsed) { $snap.metrics.contextUsed = $bs.metrics.contextUsed }
+                                if ($null -eq $snap.metrics.tokens) { $snap.metrics.tokens = $bs.metrics.tokens }
+                                if ($null -eq $snap.metrics.cacheHit) { $snap.metrics.cacheHit = $bs.metrics.cacheHit }
+                                if ($null -eq $snap.metrics.tps -and $bs.metrics.tps) { $snap.metrics.tps = $bs.metrics.tps }
+                                if (-not $snap.title -and $bs.title) { $snap.title = $bs.title }
+                                if ($bs.approx) { $snap.approx = $true }
+                            }
+                        }
+                    } catch { }
+                    Send-ToPage @{ type = 'snapshot'; data = $snap }
+                    # 每 ~5 秒记一行，用来确认数据真的到了页面
+                    $now = Get-Date
+                    if (-not $script:lastSnapLog -or ($now - $script:lastSnapLog).TotalSeconds -gt 5) {
+                        $script:lastSnapLog = $now
+                        Log "snapshot -> page: src=$($snap.source) rows=$(@($snap.messages).Count) turns=$($snap.metrics.turns) steps=$($snap.metrics.steps) tok=$($snap.metrics.tokens) ctx=$($snap.metrics.contextUsed) approx=$($snap.approx)"
+                    }
                 }
             }
         } catch { Log "snapshot error: $($_.Exception.Message)" }
@@ -471,6 +502,16 @@ $onWvReady = {
 $wv.add_CoreWebView2InitializationCompleted($onWvReady)
 $form.Add_Shown({
         Log 'form shown'
+        # 独立镜像桥：以隐藏窗口跑起来（DSH 没重启时也能出镜像与指标）
+        try {
+            if (Test-Path $bridgeScript) {
+                $nodeExe = (Get-Command node -ErrorAction SilentlyContinue).Source
+                if ($nodeExe) {
+                    $script:bridge = Start-Process -FilePath $nodeExe -ArgumentList @("`"$bridgeScript`"", '--home', "`"$DshHome`"", '--quiet') -WindowStyle Hidden -PassThru
+                    Log "mirror bridge pid=$($script:bridge.Id)"
+                } else { Log 'node not found; mirror bridge skipped' }
+            } else { Log "bridge script missing: $bridgeScript" }
+        } catch { Log "bridge start failed: $($_.Exception.Message)" }
         $form.AllowResize = -not $script:state.sizeLock
         try {
             $udf = Join-Path $stateDir 'webview2'
@@ -489,7 +530,10 @@ $form.Add_Shown({
 
 $form.Add_ResizeEnd({ if (-not $script:state.fullscreen) { $script:state.w = $form.Width; $script:state.h = $form.Height; Save-State; Push-State } })
 $form.Add_Move({ if (-not $script:state.fullscreen -and $form.WindowState -eq 'Normal') { $script:state.x = $form.Left; $script:state.y = $form.Top } })
-$form.Add_FormClosing({ Save-State })
+$form.Add_FormClosing({
+        Save-State
+        try { if ($script:bridge -and -not $script:bridge.HasExited) { $script:bridge.Kill() } } catch { }
+    })
 $form.Add_KeyDown({
         param($s, $e)
         if ($e.KeyCode -eq [System.Windows.Forms.Keys]::F11) { Toggle-Fullscreen }