Fix gitignore to allow src/lib and add missing taskCancellation utility

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

.gitignore

@@ -88,8 +88,8 @@ dist/
 downloads/
 eggs/
 .eggs/
-lib/
-lib64/
+/lib/
+/lib64/
 parts/
 sdist/
 var/

src/lib/taskCancellation.ts

@@ -0,0 +1,114 @@
+/**
+ * Task cancellation utilities for long-running generation processes.
+ */
+
+import { toast } from 'sonner';
+
+const API_BASE_URL = import.meta.env.VITE_API_BASE_URL || '/api';
+
+export interface TaskCancellationResponse {
+  success: boolean;
+  message?: string;
+  error?: string;
+}
+
+/**
+ * Cancel a task by its ID
+ */
+export async function cancelTask(taskId: string): Promise<TaskCancellationResponse> {
+  try {
+    const url = `${API_BASE_URL}/tasks/${taskId}`;
+    
+    const response = await fetch(url, {
+      method: 'DELETE',
+      headers: {
+        'Content-Type': 'application/json',
+      },
+    });
+
+    if (!response.ok) {
+      if (response.status === 404) {
+        return {
+          success: false,
+          error: 'Task not found or already completed',
+        };
+      }
+      
+      const errorData = await response.json().catch(() => ({}));
+      return {
+        success: false,
+        error: errorData.error || `Failed to cancel task: ${response.statusText}`,
+      };
+    }
+
+    const data = await response.json();
+    return {
+      success: true,
+      message: data.message || 'Task cancelled successfully',
+    };
+  } catch (error) {
+    console.error('Error cancelling task:', error);
+    return {
+      success: false,
+      error: error instanceof Error ? error.message : 'Network error while cancelling task',
+    };
+  }
+}
+
+/**
+ * Cancel a task with user feedback
+ */
+export async function cancelTaskWithFeedback(taskId: string, taskDescription: string = 'task'): Promise<boolean> {
+  try {
+    const result = await cancelTask(taskId);
+    
+    if (result.success) {
+      toast.success(result.message || `${taskDescription} cancelled successfully`);
+      return true;
+    } else {
+      toast.error(result.error || `Failed to cancel ${taskDescription}`);
+      return false;
+    }
+  } catch (error) {
+    console.error('Error cancelling task with feedback:', error);
+    toast.error(`Failed to cancel ${taskDescription}`);
+    return false;
+  }
+}
+
+/**
+ * Hook-style function for creating a cancellation handler
+ */
+export function useCancellationHandler(taskId: string | null, onCancel?: () => void) {
+  return async () => {
+    if (!taskId) {
+      console.warn('No task ID available for cancellation');
+      return false;
+    }
+
+    const success = await cancelTaskWithFeedback(taskId, 'generation');
+    
+    if (success && onCancel) {
+      onCancel();
+    }
+    
+    return success;
+  };
+}
+
+/**
+ * Utility for handling WebSocket cancellation events
+ */
+export function handleWebSocketCancellation(
+  taskId: string,
+  onCancelled: () => void,
+  taskDescription: string = 'task'
+) {
+  // This will be implemented when we add WebSocket support
+  return (event: any) => {
+    if (event.task_id === taskId && event.type === 'task_cancelled') {
+      toast.info(`${taskDescription} was cancelled`);
+      onCancelled();
+    }
+  };
+}