fix(input): count code points when clearing prompts

src/web/public/keyboard-accessory.js

@@ -1156,13 +1156,13 @@ const KeyboardAccessoryBar = {
     const pending = app._localEchoOverlay.pendingText || '';
     const overlayFlushed = app._localEchoOverlay.getFlushed?.() || {};
     const flushedText = overlayFlushed.text || app._flushedTexts?.get(sessionId) || '';
-    const flushedCount = overlayFlushed.count || app._flushedOffsets?.get(sessionId) || 0;
+    const flushedLength = Array.from(flushedText).length;
     app._localEchoOverlay.clear();
     app._localEchoOverlay.suppressBufferDetection?.();
     app._flushedOffsets?.delete(sessionId);
     app._flushedTexts?.delete(sessionId);
-    if (flushedCount > 0) {
+    if (flushedLength > 0) {
-      app._sendInputAsync(sessionId, '\x7f'.repeat(flushedCount), { useMux: true });
+      app._sendInputAsync(sessionId, '\x7f'.repeat(flushedLength), { useMux: true });
     }
     return flushedText + pending;
   },

src/web/public/terminal-ui.js

@@ -4069,8 +4069,9 @@ Object.assign(CodemanApp.prototype, {
       this._localEchoOverlay.suppressBufferDetection();
       this._flushedOffsets?.delete(this.activeSessionId);
       this._flushedTexts?.delete(this.activeSessionId);
-      if (flushed.count > 0) {
+      const flushedLength = Array.from(flushed.text || '').length;
-        this.sendInput('\x7f'.repeat(flushed.count)).catch(() => {});
+      if (flushedLength > 0) {
+        this.sendInput('\x7f'.repeat(flushedLength)).catch(() => {});
       }
     } else {
       // In non-local-echo mode the TUI already owns the editable buffer. Ctrl+U

test/mobile-prompt-composer.test.ts

@@ -152,6 +152,17 @@ describe('mobile prompt composer', () => {
     expect(app._flushedTexts.has('session-1')).toBe(false);
   });
 
+  it('uses Unicode code points when erasing flushed text', () => {
+    const { app, bar, document } = loadComposer();
+    app._flushedOffsets.set('session-1', 3);
+    app._flushedTexts.set('session-1', 'a😀');
+
+    bar.composePrompt();
+
+    expect(textarea(document).value).toBe('a😀');
+    expect(app._sendInputAsync).toHaveBeenCalledWith('session-1', '\x7f'.repeat(2), { useMux: true });
+  });
+
   it('closes on tab switch and keeps drafts isolated by session', () => {
     const { app, bar, document } = loadComposer();
     const composeButton = mountComposeButton(bar, document);

test/path-picker-ui.test.ts

@@ -200,12 +200,12 @@ describe('mobile filesystem picker actions', () => {
       _pendingInput: 'pending text',
       _localEchoEnabled: true,
       _localEchoOverlay: {
-        getFlushed: () => ({ count: 4, text: 'sent' }),
+        getFlushed: () => ({ count: 4, text: 'a😀b' }),
         clear,
         suppressBufferDetection,
       },
       _flushedOffsets: new Map([['session-1', 4]]),
-      _flushedTexts: new Map([['session-1', 'sent']]),
+      _flushedTexts: new Map([['session-1', 'a😀b']]),
       sendInput,
       showToast,
       terminal: { focus },
@@ -216,7 +216,7 @@ describe('mobile filesystem picker actions', () => {
     expect(app._pendingInput).toBe('');
     expect(clear).toHaveBeenCalledOnce();
     expect(suppressBufferDetection).toHaveBeenCalledOnce();
-    expect(sendInput).toHaveBeenCalledWith('\x7f'.repeat(4));
+    expect(sendInput).toHaveBeenCalledWith('\x7f'.repeat(3));
     expect(sendInput).not.toHaveBeenCalledWith('/clear');
     expect(app._flushedOffsets.size).toBe(0);
     expect(app._flushedTexts.size).toBe(0);