fix(input): force Genshin foreground via AttachThreadInput (auto-scan no longer aborts)

Auto-scan aborted immediately with "Genshin konnte nicht in den Vordergrund
geholt werden". Root cause: the focus call runs in the background input/capture
helper process, and Windows' foreground lock silently refuses SetForegroundWindow
from a process that is neither foreground nor the last input source. When the user
clicks "Auto-Scan starten" the Electron window is foreground, so the helper's plain
SetForegroundWindow is dropped and focus stays false.

Fix (both the C# sidecar and the PowerShell fallback): before SetForegroundWindow,
attach our thread's input queue to the target (and current-foreground) window
thread with AttachThreadInput and clear SPI_..FOREGROUNDLOCKTIMEOUT, then restore.
This is the same technique Inventory Kamera and other reliable automators use; it
is what our helper was missing after the old ALT-tap workaround was removed on the
wrong assumption that equal integrity level is sufficient (that only covers UIPI
input injection, not foreground changes).

Sidecar recompiled + republished; electron build green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

electron/preload.cjs

@@ -11,6 +11,7 @@ contextBridge.exposeInMainWorld("assistantApi", {
   getAutomationGuard: () => ipcRenderer.invoke("automation:getGuard"),
   focusMainWindow: () => ipcRenderer.invoke("app:focusMainWindow"),
   focusGenshin: () => ipcRenderer.invoke("automation:focusGenshin"),
+  focusGenshinForScanStart: () => ipcRenderer.invoke("automation:focusGenshin"),
   getRuntimeInfo: () => ipcRenderer.invoke("app:getRuntimeInfo"),
   saveReviewSample: (sample) => ipcRenderer.invoke("review:saveSample", sample),
   loadReviewSamples: (limit = 50) => ipcRenderer.invoke("review:loadSamples", limit),

electron/preload.ts

@@ -14,6 +14,7 @@ contextBridge.exposeInMainWorld("assistantApi", {
   getAutomationGuard: () => ipcRenderer.invoke("automation:getGuard"),
   focusMainWindow: () => ipcRenderer.invoke("app:focusMainWindow"),
   focusGenshin: () => ipcRenderer.invoke("automation:focusGenshin"),
+  focusGenshinForScanStart: () => ipcRenderer.invoke("automation:focusGenshin"),
   getRuntimeInfo: () => ipcRenderer.invoke("app:getRuntimeInfo"),
   saveReviewSample: (sample: ReviewSamplePayload) => ipcRenderer.invoke("review:saveSample", sample),
   loadReviewSamples: (limit = 50) => ipcRenderer.invoke("review:loadSamples", limit),

electron/services/inputHelper.ts

@@ -39,6 +39,16 @@ public static extern bool SetForegroundWindow(IntPtr hWnd);
 [DllImport("user32.dll")]
 public static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);
 [DllImport("user32.dll")]
+public static extern bool BringWindowToTop(IntPtr hWnd);
+[DllImport("user32.dll", SetLastError=true)]
+public static extern bool AttachThreadInput(uint idAttach, uint idAttachTo, bool fAttach);
+[DllImport("kernel32.dll")]
+public static extern uint GetCurrentThreadId();
+[DllImport("user32.dll", SetLastError=true, EntryPoint="SystemParametersInfoW")]
+public static extern bool SystemParametersInfoGet(uint uiAction, uint uiParam, ref uint pvParam, uint fWinIni);
+[DllImport("user32.dll", SetLastError=true, EntryPoint="SystemParametersInfoW")]
+public static extern bool SystemParametersInfoSet(uint uiAction, uint uiParam, IntPtr pvParam, uint fWinIni);
+[DllImport("user32.dll")]
 public static extern IntPtr GetForegroundWindow();
 [DllImport("user32.dll")]
 public static extern bool IsWindow(IntPtr hWnd);
@@ -181,6 +191,41 @@ function Find-GenshinWindow {
   return $script:genshinHwnd
 }
 
+# Plain SetForegroundWindow from this background helper process is silently
+# refused by Windows' foreground lock. Attach our thread's input queue to the
+# target (and current foreground) window thread and clear the lock timeout, so
+# the foreground change is honored - the same technique Inventory Kamera uses.
+function Force-Foreground {
+  param([IntPtr]$hwnd)
+  $current = [Native.InputHelper]::GetCurrentThreadId()
+  $targetPid = [uint32]0
+  $target = [Native.InputHelper]::GetWindowThreadProcessId($hwnd, [ref]$targetPid)
+  $fgWindow = [Native.InputHelper]::GetForegroundWindow()
+  $foreground = [uint32]0
+  if ($fgWindow -ne [IntPtr]::Zero) {
+    $fgPid = [uint32]0
+    $foreground = [Native.InputHelper]::GetWindowThreadProcessId($fgWindow, [ref]$fgPid)
+  }
+
+  $attachedTarget = $false
+  $attachedForeground = $false
+  $oldTimeout = [uint32]0
+  $timeoutRead = $false
+  try {
+    if ($target -ne 0 -and $target -ne $current) { $attachedTarget = [Native.InputHelper]::AttachThreadInput($current, $target, $true) }
+    if ($foreground -ne 0 -and $foreground -ne $current -and $foreground -ne $target) { $attachedForeground = [Native.InputHelper]::AttachThreadInput($current, $foreground, $true) }
+    $timeoutRead = [Native.InputHelper]::SystemParametersInfoGet(0x2000, 0, [ref]$oldTimeout, 0)
+    [Native.InputHelper]::SystemParametersInfoSet(0x2001, 0, [IntPtr]::Zero, 0x0002) | Out-Null
+    [Native.InputHelper]::ShowWindowAsync($hwnd, 9) | Out-Null
+    [Native.InputHelper]::BringWindowToTop($hwnd) | Out-Null
+    return [Native.InputHelper]::SetForegroundWindow($hwnd)
+  } finally {
+    if ($timeoutRead) { [Native.InputHelper]::SystemParametersInfoSet(0x2001, 0, [IntPtr]::new([int64]$oldTimeout), 0x0002) | Out-Null }
+    if ($attachedForeground) { [Native.InputHelper]::AttachThreadInput($current, $foreground, $false) | Out-Null }
+    if ($attachedTarget) { [Native.InputHelper]::AttachThreadInput($current, $target, $false) | Out-Null }
+  }
+}
+
 function Focus-GenshinWindow {
   $hwnd = Find-GenshinWindow
   $info = @{
@@ -194,19 +239,7 @@ function Focus-GenshinWindow {
 
   $info.alreadyForeground = ([Native.InputHelper]::GetForegroundWindow() -eq $hwnd)
   if (-not $info.alreadyForeground) {
-    [Native.InputHelper]::ShowWindowAsync($hwnd, 9) | Out-Null
-    # A previous version tapped ALT (keybd_event) right before this call to
-    # satisfy Windows' "who's allowed to change the foreground window"
-    # eligibility check. That tap has a side effect in most Win32 apps: a
-    # bare ALT press/release toggles menu-mnemonic navigation mode (verified
-    # live - it left a real app's menu bar highlighted after just this call),
-    # which then swallows the next several keyboard/mouse events as menu
-    # navigation instead of routing them to the app - looking exactly like
-    # "clicks/keys report success but do nothing". This app and Genshin run
-    # at the same (elevated) integrity level, so plain SetForegroundWindow
-    # already succeeds without the ALT tap - confirmed with a standalone
-    # compiled test against a live target window.
-    $info.setForegroundResult = [Native.InputHelper]::SetForegroundWindow($hwnd)
+    $info.setForegroundResult = Force-Foreground -hwnd $hwnd
     Start-Sleep -Milliseconds 140
   }