Diagnose and patch Linux key event routing (WIP)

Add temporary logging and diagnostic patches for Linux/Wayland key event
input issues:

- Log all Tao key events (KEY_DOWN/UP/TYPED) with vk code, modifiers, codepoint
- Disable permanent super_key() state from taffy that contaminates Tab/Backspace
  with unwanted Meta modifier
- Fall through ModifiersChanged to emit KeyboardInput for modifier-only presses
  (Alt/Ctrl/Shift/Super release now observable on Linux vs upstream tao)

Diagnostic code — remove once input routing is verified.

Author: kdroidFilter

decorated-window-tao/src/main/kotlin/dev/nucleusframework/window/tao/render/TaoComposeSceneHostLinux.kt

@@ -1021,6 +1021,21 @@ internal class TaoComposeSceneHostLinux(
         modifiers: Int,
         codePoint: Int,
     ): Boolean {
+        // TEMPORARY DIAGNOSTIC — log every Tao key event reaching the scene host
+        // so we can correlate user-visible bugs (Tab triggering shortcut without
+        // Alt, Backspace not deleting in TextField) with the exact native event
+        // shape (vk code, modifier bitmask, codePoint) Tao forwards from libtao.
+        // Remove once the input routing is verified.
+        val typeName =
+            when (type) {
+                TaoEventCode.KEY_DOWN -> "KEY_DOWN"
+                TaoEventCode.KEY_UP -> "KEY_UP"
+                TaoEventCode.KEY_TYPED -> "KEY_TYPED"
+                else -> "OTHER($type)"
+            }
+        println(
+            "[TAO_KEY] $typeName vk=$vkCode loc=$keyLocation mods=0b${modifiers.toString(2).padStart(4, '0')} cp=$codePoint",
+        )
         val sc = scene ?: return false
         val isCtrl = (modifiers and TaoModifierMask.CONTROL) != 0
         val isMeta = (modifiers and TaoModifierMask.META) != 0

decorated-window-tao/src/main/native/src/events.rs

@@ -22,7 +22,12 @@ pub(crate) fn pack_modifiers(state: ModifiersState) -> i32 {
     if state.shift_key() { m |= MOD_MASK_SHIFT; }
     if state.control_key() { m |= MOD_MASK_CONTROL; }
     if state.alt_key() { m |= MOD_MASK_ALT; }
-    if state.super_key() { m |= MOD_MASK_META; }
+    // DIAGNOSTIC (Linux/Wayland): super_key() returns true permanently on some
+    // compositors after the first ModifiersChanged tick, contaminating every
+    // subsequent key event (Tab gets Meta, Backspace gets Meta → TextField
+    // mapping fails). Temporarily disabled while we verify the workaround
+    // approach. Re-enable once a per-key SuperLeft/SuperRight tracker is in.
+    let _ = state.super_key();
     m
 }
 

decorated-window-tao/src/main/native/vendor/tao/src/platform_impl/linux/event_loop.rs

@@ -727,11 +727,14 @@ impl<T: 'static> EventLoop<T> {
                     "Failed to send modifiers changed event to event channel: {}",
                     e
                   );
-                } else {
-                  // stop here we don't want to send the key event
-                  // as we emit the `ModifiersChanged`
-                  return glib::ControlFlow::Continue;
                 }
+                // Nucleus patch: fall through and *also* emit `KeyboardInput`
+                // for modifier-only keypresses so the JVM side can observe Alt
+                // / Ctrl / Shift / Super press/release as plain Compose key
+                // events (needed by app-level handlers like
+                // `(ev.key == Key.AltLeft) && ev.type == KeyEventType.KeyUp`).
+                // Upstream tao stops here, which makes those handlers dead on
+                // the Linux backend.
               }
 
               // todo: implement repeat?