fix: keep Cua foreground actions on the target window

tests/capture-fixture.ps1

@@ -1,4 +1,4 @@
-param([string]$Title, [string]$ReadyFile, [switch]$Cover, [int]$Width=500, [int]$Height=300, [switch]$PerMonitorDpi)
+param([string]$Title, [string]$ReadyFile, [switch]$Cover, [int]$Width=500, [int]$Height=300, [switch]$PerMonitorDpi, [switch]$NormalWindow)
 if ($PerMonitorDpi) {
     Add-Type -TypeDefinition 'using System; using System.Runtime.InteropServices; public static class FixtureDpi { [DllImport("user32.dll")] public static extern IntPtr SetThreadDpiAwarenessContext(IntPtr c); }'
     [void][FixtureDpi]::SetThreadDpiAwarenessContext([IntPtr](-4))
@@ -10,7 +10,7 @@ $form.Text = $Title
 $form.Size = New-Object System.Drawing.Size($Width, $Height)
 $form.StartPosition = 'Manual'
 $form.Location = New-Object System.Drawing.Point(100, 100)
-$form.TopMost = $true
+$form.TopMost = -not $NormalWindow
 $form.BackColor = if ($Cover) { [System.Drawing.Color]::Magenta } else { [System.Drawing.Color]::Lime }
 $label = New-Object System.Windows.Forms.Label
 $label.Text = if ($Cover) { 'OCCLUDER - NOT TEST EVIDENCE' } else { 'ARTEMIS window capture fixture' }

tests/cua_browser_smoke.py

@@ -22,6 +22,7 @@ import jsonschema
 import psutil
 from artemis.plugins.models import ServerConfig
 from artemis.plugins.session import PluginSession
+from artemis.runtime.device_lock import DeviceExecutionLock
 
 
 async def model_task(base, pid, url, output, events, traces, model):
@@ -133,6 +134,7 @@ async def run(
     base=None,
     traces=None,
     model="gpt-6.1-sol",
+    foreground_check=False,
 ):
     output.mkdir(parents=True, exist_ok=True)
     events = []
@@ -179,7 +181,7 @@ async def run(
     threading.Thread(target=server.serve_forever, daemon=True).start()
     url = f"http://127.0.0.1:{server.server_port}"
     session = None
-    process = None
+    process = cover_process = None
     try:
         with tempfile.TemporaryDirectory(prefix="artemis-cua-browser-") as profile:
             try:
@@ -276,6 +278,60 @@ async def run(
                     assert match, state["tree_markdown"]
                     return state["snapshot_id"] + ":" + match[1]
 
+                if foreground_check:
+                    ready = Path(profile) / "cover-ready"
+                    cover_process = await asyncio.create_subprocess_exec(
+                        "powershell.exe",
+                        "-NoProfile",
+                        "-File",
+                        str(Path(__file__).with_name("capture-fixture.ps1")),
+                        "-Title",
+                        "ARTEMIS foreground handoff fixture",
+                        "-ReadyFile",
+                        str(ready),
+                        "-Cover",
+                        "-NormalWindow",
+                        "-Width",
+                        "1100",
+                        "-Height",
+                        "900",
+                        stdout=subprocess.DEVNULL,
+                        stderr=subprocess.DEVNULL,
+                        creationflags=subprocess.CREATE_NO_WINDOW,
+                    )
+                    async with asyncio.timeout(20):
+                        while not ready.exists():
+                            await asyncio.sleep(0.1)
+                    cover_windows = await call(
+                        "list_windows", {"pid": cover_process.pid}
+                    )
+                    cover = {
+                        k: cover_windows["windows"][0][k] for k in ("pid", "window_id")
+                    }
+                    await call("bring_to_front", cover)
+                    hidden = await observe()
+                    assert not hidden["capture_focus"]["target_foreground_before"]
+                    assert not hidden["capture_focus"]["target_foreground_after"]
+                    # Explicit foreground input must not snap back to the cover.
+                    await key("l", ["ctrl"])
+                    await asyncio.sleep(5)  # Past Cua's 3-second restore poller.
+                    focused = await observe()
+                    assert focused["capture_focus"]["target_foreground_after"]
+                    await key("escape")
+                    # Manual focus loss is reported, never silently corrected by
+                    # read-only capture. Existing bring_to_front recovers it.
+                    await call("bring_to_front", cover)
+                    hidden = await observe()
+                    assert not hidden["capture_focus"]["target_foreground_after"]
+                    await call("bring_to_front", target)
+                    await asyncio.sleep(5)
+                    focused = await observe()
+                    assert focused["capture_focus"]["target_foreground_before"]
+                    assert focused["capture_focus"]["target_foreground_after"]
+                    await call(
+                        "save_screenshot",
+                        {**target, "filename": "foreground-recovered.png"},
+                    )
                 await wait_tree("ARTEMIS Cua Browser Start")
                 # Reproduce task f1928... invalid form before any keyboard dispatch.
                 bad = await call(
@@ -303,6 +359,11 @@ async def run(
                 )
                 await key("return")
                 state = await wait_tree("Test parameter")
+                if foreground_check:
+                    await asyncio.sleep(5)
+                    state = await observe()
+                    assert state["capture_focus"]["target_foreground_after"]
+                    assert "Test parameter" in state["tree_markdown"]
                 # Direct UIA replacement is a separate, unambiguous tool.
                 await call(
                     "set_value",
@@ -393,6 +454,7 @@ async def run(
                 )
                 report = {
                     "passed": True,
+                    "foreground_handoff_and_readonly_recovery": foreground_check,
                     "checks": [
                         "mixed parameters refused before dispatch",
                         "Ctrl+T new tab",
@@ -417,6 +479,9 @@ async def run(
                 )
                 if session:
                     await session.aclose()
+                if cover_process and cover_process.returncode is None:
+                    cover_process.terminate()
+                    await cover_process.wait()
                 if process:
                     try:
                         parent = psutil.Process(process.pid)
@@ -449,16 +514,32 @@ if __name__ == "__main__":
         "--traces", type=Path, help="That server's traces directory (model test only)"
     )
     parser.add_argument("--model", default="gpt-6.1-sol")
+    parser.add_argument("--foreground-check", action="store_true")
     args = parser.parse_args()
     if args.model_base and not args.traces:
         parser.error("--model-base requires --traces")
-    asyncio.run(
-        run(
-            args.executable.resolve(),
-            args.browser,
-            args.output.resolve(),
-            args.model_base,
-            args.traces,
-            args.model,
+    if args.foreground_check and args.model_base:
+        parser.error("--foreground-check is deterministic, not a model task")
+    lock = None
+    if not args.model_base:
+        lock = DeviceExecutionLock(
+            "cua-browser-regression",
+            description="Cua browser regression",
+            resource_ids=["desktop:local"],
         )
-    )
+        lock.acquire(timeout=0)
+    try:
+        asyncio.run(
+            run(
+                args.executable.resolve(),
+                args.browser,
+                args.output.resolve(),
+                args.model_base,
+                args.traces,
+                args.model,
+                args.foreground_check,
+            )
+        )
+    finally:
+        if lock:
+            lock.release()