fix: Block triggering key after composition end

When pressing space or period to end Korean IME composition, the keydown
event fires before compositionend. This caused the triggering character
to be output before the composed text (e.g., "세요" becomes "세 요").

Added compositionJustEnded flag that blocks the first keydown after
composition ends, preventing the character order reversal.

Fixes hongsw#1

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: aibaryonai-ctrl

lib/input-handler.ts

@@ -195,6 +195,7 @@ export class InputHandler {
   private mousemoveListener: ((e: MouseEvent) => void) | null = null;
   private wheelListener: ((e: WheelEvent) => void) | null = null;
   private isComposing = false;
+  private compositionJustEnded = false; // Block keydown briefly after composition ends
   private isDisposed = false;
   private mouseButtonsPressed = 0; // Track which buttons are pressed for motion reporting
   private lastKeyDownData: string | null = null;
@@ -374,6 +375,13 @@ export class InputHandler {
       return;
     }
 
+    // Block the key that triggered composition end (e.g., space, period)
+    // This fixes the "세요" -> "세 요" bug where keydown fires before compositionend
+    if (this.compositionJustEnded) {
+      this.compositionJustEnded = false;
+      return;
+    }
+
     // Emit onKey event first (before any processing)
     if (this.onKeyCallback) {
       this.onKeyCallback({ key: event.key, domEvent: event });
@@ -690,6 +698,14 @@ export class InputHandler {
     if (this.isDisposed) return;
     this.isComposing = false;
 
+    // Set flag to block the next keydown event (the key that triggered composition end)
+    // This prevents "세요" becoming "세 요" when space/period is pressed
+    this.compositionJustEnded = true;
+    // Clear flag after a short delay to allow normal keydown processing
+    setTimeout(() => {
+      this.compositionJustEnded = false;
+    }, 10);
+
     const data = event.data;
     if (data && data.length > 0) {
       if (this.shouldIgnoreCompositionEnd(data)) {