feat: per-window detection — only flash windows needing attention

Detector now walks each AXWindow subtree independently and returns
both aggregate signals (for state machine) and a list of AXWindow
element refs for windows with active approval signals.

Overlay reads position/size directly from AXWindow elements via
AXValueGetValue, eliminating the CGWindowList dependency (which
returned empty names for Electron windows anyway).

Daemon passes only the active AXWindow refs to the overlay, so
only the specific window(s) waiting for user input get flashed.

Made-with: Cursor

scripts/test_overlay.py

@@ -1,7 +1,16 @@
-"""Manual test: shows a pulsing border around Cursor for 10 seconds."""
+"""Manual test: shows a pulsing border around Cursor windows for 10 seconds.
+
+With no args, flashes all windows (for visual testing).
+With --per-window, only flashes windows with active signals (production behavior).
+"""
+import argparse
 import sys
 import time
 
+from ApplicationServices import (
+    AXUIElementCreateApplication,
+    AXUIElementCopyAttributeValue,
+)
 from Cocoa import NSApplication, NSRunLoop, NSDate
 
 from cursor_flasher.config import Config
@@ -10,6 +19,11 @@ from cursor_flasher.detector import CursorDetector
 
 app = NSApplication.sharedApplication()
 
+parser = argparse.ArgumentParser()
+parser.add_argument("--per-window", action="store_true",
+                    help="Only flash windows that need attention")
+args = parser.parse_args()
+
 config = Config()
 overlay = OverlayManager(config)
 detector = CursorDetector()
@@ -19,8 +33,24 @@ if pid is None:
     print("Cursor not running")
     sys.exit(1)
 
-print(f"Showing overlay for PID {pid} for 10 seconds...")
-overlay.show(pid)
+if args.per_window:
+    result = detector.poll()
+    if result is None or not result.active_windows:
+        print("No windows currently need attention")
+        sys.exit(0)
+    ax_windows = result.active_windows
+    print(f"Flashing {len(ax_windows)} window(s) that need attention...")
+else:
+    app_element = AXUIElementCreateApplication(pid)
+    _, children = AXUIElementCopyAttributeValue(app_element, "AXChildren", None)
+    ax_windows = []
+    for child in children:
+        _, role = AXUIElementCopyAttributeValue(child, "AXRole", None)
+        if str(role) == "AXWindow":
+            ax_windows.append(child)
+    print(f"Flashing all {len(ax_windows)} Cursor window(s)...")
+
+overlay.show(ax_windows)
 
 end_time = time.time() + 10
 while time.time() < end_time: