feat: add swipe functionality for multiple response alternatives

- Added swipe system to Message struct with backward compatibility
- Implemented swipe navigation UI with left/right arrows and counter
- Added generate_response_only and generate_response_stream commands
- Swipes persist properly when navigating between alternatives
- Updated message rendering to support swipe controls

src/styles.css

@@ -231,6 +231,7 @@ body {
 .message {
   display: flex;
   animation: slideIn 0.3s ease;
+  position: relative;
 }
 
 @keyframes slideIn {
@@ -286,6 +287,182 @@ body {
   margin-top: 12px;
 }
 
+/* Message action buttons */
+.message-actions {
+  position: absolute;
+  top: 8px;
+  display: flex;
+  gap: 4px;
+  opacity: 0;
+  transition: opacity 0.2s ease;
+}
+
+.message.user .message-actions {
+  right: 8px;
+}
+
+.message.assistant .message-actions {
+  right: 8px;
+}
+
+.message:hover .message-actions {
+  opacity: 1;
+}
+
+.message-action-btn {
+  width: 24px;
+  height: 24px;
+  border: none;
+  background: rgba(0, 0, 0, 0.5);
+  backdrop-filter: blur(8px);
+  -webkit-backdrop-filter: blur(8px);
+  border-radius: 6px;
+  color: var(--text-secondary);
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  transition: all 0.2s ease;
+  padding: 0;
+}
+
+.message-action-btn:hover {
+  background: rgba(0, 0, 0, 0.7);
+  color: var(--text-primary);
+  transform: scale(1.1);
+}
+
+.message-action-btn:active {
+  transform: scale(0.9);
+}
+
+.message-action-btn svg {
+  width: 14px;
+  height: 14px;
+}
+
+/* Swipe navigation */
+.swipe-controls {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  margin-top: 8px;
+  padding: 4px 8px;
+  background: rgba(0, 0, 0, 0.3);
+  border-radius: 12px;
+  width: fit-content;
+  opacity: 0;
+  transition: opacity 0.2s ease;
+}
+
+.message.assistant:hover .swipe-controls {
+  opacity: 1;
+}
+
+.swipe-controls.always-visible {
+  opacity: 1;
+}
+
+.swipe-btn {
+  width: 20px;
+  height: 20px;
+  border: none;
+  background: rgba(255, 255, 255, 0.1);
+  color: var(--text-secondary);
+  border-radius: 50%;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  transition: all 0.2s ease;
+  padding: 0;
+}
+
+.swipe-btn:hover:not(:disabled) {
+  background: rgba(255, 255, 255, 0.2);
+  color: var(--text-primary);
+}
+
+.swipe-btn:disabled {
+  opacity: 0.3;
+  cursor: not-allowed;
+}
+
+.swipe-btn svg {
+  width: 12px;
+  height: 12px;
+}
+
+.swipe-counter {
+  font-size: 11px;
+  color: var(--text-secondary);
+  min-width: 32px;
+  text-align: center;
+  user-select: none;
+}
+
+/* Edit mode for messages */
+.message-edit-form {
+  width: 100%;
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.message-edit-textarea {
+  width: 100%;
+  background: var(--bg-tertiary);
+  border: 1px solid var(--accent);
+  border-radius: 8px;
+  padding: 12px;
+  color: var(--text-primary);
+  font-size: 14px;
+  font-family: inherit;
+  resize: vertical;
+  min-height: 60px;
+}
+
+.message-edit-textarea:focus {
+  outline: none;
+  border-color: var(--accent-hover);
+}
+
+.message-edit-actions {
+  display: flex;
+  gap: 8px;
+  justify-content: flex-end;
+}
+
+.message-edit-btn {
+  padding: 6px 12px;
+  border: none;
+  border-radius: 6px;
+  font-size: 12px;
+  font-weight: 500;
+  cursor: pointer;
+  transition: all 0.2s ease;
+  font-family: inherit;
+}
+
+.message-edit-btn.save {
+  background: var(--accent);
+  color: white;
+}
+
+.message-edit-btn.save:hover {
+  background: var(--accent-hover);
+}
+
+.message-edit-btn.cancel {
+  background: var(--bg-tertiary);
+  color: var(--text-primary);
+  border: 1px solid var(--border);
+}
+
+.message-edit-btn.cancel:hover {
+  background: var(--border);
+}
+
 .message-content code {
   background: rgba(0, 0, 0, 0.3);
   padding: 2px 6px;