Windows: dropping a file on the island does nothing ("no drop" cursor, no drag lines in the log) #126

What happened

On Windows, dragging a file from Explorer onto the island never works. The cursor shows the "no drop" sign (🚫) over the island, nothing is copied to the inbox, and no drag line is ever written to coucou.log.

What you expected

The file is accepted and copied to the inbox, and drag enter / drag drop lines appear in the log.

How to reproduce

1. Run windows\target\release\coucou.exe (built from source, commit 7ce5480).
2. Hover the island so it expands, then click the "+" tab ("Drop your files here").
3. Drag a file (e.g. a PDF) from Explorer onto the island and release.
4. Result: 🚫 cursor, nothing happens.

What I checked:

• Not elevated (Task Manager: Elevated = No), single monitor.

• Tried at 100% and 200% display scaling.

• Toggled Pause on and off twice and restarted the app several times. No change.

• The island's eyes follow the cursor while dragging, so the cursor poll works.

• The frontend can write to the log. In the same session coucou.log shows:

  hook PermissionRequest id=17008-1
  ui  decide allow req=17008-1
  decision id=17008-1 allow
  hook id=17008-1 answered allow
  

• But during the drag attempts there are no drag enter / drag drop / drag leave lines at all, so the drop event seems to never reach the WebView.

• The unblock_webview_drops workaround from 5c82c1a is in my build and doesn't help.

macOS version

N/A (Windows 11 Pro 26H2, OS Build 26300.9457, WebView2 Runtime 154.0.4258.48)

Mac model

N/A (Windows PC)

Coucou version

0.1.1, built from source (commit 7ce5480)