fix: prevent clipboard overwrite on single click without selection (#124)

The mouseup handler in SelectionManager was calling copyToClipboard()
without first checking hasSelection(), causing single clicks on terminal
cells to copy the character at that position to the clipboard. This
overwrote the user's clipboard contents unexpectedly.

Added a hasSelection() guard in the mouseup handler to match the pattern
already used in the public copySelection() API.

Fixes #108

Co-authored-by: Yansu <no-reply@yansu.ai>
Co-authored-by: Claude <noreply@anthropic.com>

Author: 3 people

lib/selection-manager.ts

@@ -550,10 +550,12 @@ export class SelectionManager {
         this.isSelecting = false;
         this.stopAutoScroll();
 
-        const text = this.getSelection();
-        if (text) {
-          this.copyToClipboard(text);
-          this.selectionChangedEmitter.fire();
+        if (this.hasSelection()) {
+          const text = this.getSelection();
+          if (text) {
+            this.copyToClipboard(text);
+            this.selectionChangedEmitter.fire();
+          }
         }
       }
     };