fix: Korean/CJK IME composition events not captured

IME composition events (compositionstart, compositionupdate, compositionend)
fire on the focused element. When using a hidden textarea for input,
the textarea receives focus, but composition event listeners were attached
to the container element, causing the events to be missed.

Changes:
- input-handler.ts: Attach composition events to inputElement (textarea)
  if available, otherwise fall back to container
- terminal.ts: Focus textarea instead of container in focus() method
- selection-manager.ts: Skip wide character continuation cells when
  extracting selection text (fixes spaces between CJK characters)

This fixes Korean, Chinese, Japanese and other IME input methods.

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

Author: aibaryonai-ctrl

lib/input-handler.ts

@@ -288,14 +288,19 @@ export class InputHandler {
       this.inputElement.addEventListener('beforeinput', this.beforeInputListener);
     }
 
+    // Attach composition events to inputElement (textarea) if available.
+    // IME composition events fire on the focused element, and when using a hidden
+    // textarea for input (as ghostty-web does), the textarea receives focus,
+    // not the container. This fixes Korean/Chinese/Japanese IME input.
+    const compositionTarget = this.inputElement || this.container;
     this.compositionStartListener = this.handleCompositionStart.bind(this);
-    this.container.addEventListener('compositionstart', this.compositionStartListener);
+    compositionTarget.addEventListener('compositionstart', this.compositionStartListener);
 
     this.compositionUpdateListener = this.handleCompositionUpdate.bind(this);
-    this.container.addEventListener('compositionupdate', this.compositionUpdateListener);
+    compositionTarget.addEventListener('compositionupdate', this.compositionUpdateListener);
 
     this.compositionEndListener = this.handleCompositionEnd.bind(this);
-    this.container.addEventListener('compositionend', this.compositionEndListener);
+    compositionTarget.addEventListener('compositionend', this.compositionEndListener);
 
     // Mouse event listeners (for terminal mouse tracking)
     this.mousedownListener = this.handleMouseDown.bind(this);
@@ -1059,18 +1064,20 @@ export class InputHandler {
       this.beforeInputListener = null;
     }
 
+    // Remove composition listeners from the same element they were attached to
+    const compositionTarget = this.inputElement || this.container;
     if (this.compositionStartListener) {
-      this.container.removeEventListener('compositionstart', this.compositionStartListener);
+      compositionTarget.removeEventListener('compositionstart', this.compositionStartListener);
       this.compositionStartListener = null;
     }
 
     if (this.compositionUpdateListener) {
-      this.container.removeEventListener('compositionupdate', this.compositionUpdateListener);
+      compositionTarget.removeEventListener('compositionupdate', this.compositionUpdateListener);
       this.compositionUpdateListener = null;
     }
 
     if (this.compositionEndListener) {
-      this.container.removeEventListener('compositionend', this.compositionEndListener);
+      compositionTarget.removeEventListener('compositionend', this.compositionEndListener);
       this.compositionEndListener = null;
     }
 

lib/selection-manager.ts

@@ -180,7 +180,12 @@ export class SelectionManager {
           if (char.trim()) {
             lastNonEmpty = lineText.length;
           }
-        } else {
+        } else if (!cell || cell.width !== 0) {
+          // Only add space for truly empty cells, not wide character continuation cells.
+          // Wide characters (like CJK) occupy 2 terminal cells:
+          // - First cell: has codepoint, width=2
+          // - Second cell: codepoint=0, width=0 (continuation marker)
+          // We skip continuation cells to avoid inserting spaces between characters.
           lineText += ' ';
         }
       }

lib/terminal.ts

@@ -717,15 +717,21 @@ export class Terminal implements ITerminalCore {
    * Focus terminal input
    */
   focus(): void {
-    if (this.isOpen && this.element) {
-      // Focus immediately for immediate keyboard/wheel event handling
-      this.element.focus();
-
-      // Also schedule a delayed focus as backup to ensure it sticks
-      // (some browsers may need this if DOM isn't fully settled)
-      setTimeout(() => {
-        this.element?.focus();
-      }, 0);
+    if (this.isOpen) {
+      // Focus the textarea for keyboard/IME input.
+      // The textarea is the actual input element that receives keyboard events
+      // and IME composition events. Focusing the container doesn't work for IME
+      // because composition events fire on the focused element.
+      const target = this.textarea || this.element;
+      if (target) {
+        target.focus();
+
+        // Also schedule a delayed focus as backup to ensure it sticks
+        // (some browsers may need this if DOM isn't fully settled)
+        setTimeout(() => {
+          target?.focus();
+        }, 0);
+      }
     }
   }