Add new fields to TasksSerializer and enhance auto_generate_content_task with detailed step tracking

- Updated TasksSerializer to include 'primary_keyword', 'secondary_keywords', 'tags', and 'categories'.
- Enhanced auto_generate_content_task to track progress with detailed steps, including initialization, preparation, AI call, parsing, and saving.
- Updated progress modal to reflect new phases and improved animation for smoother user experience.
- Adjusted routing and configuration for content and drafts pages in the frontend.

frontend/src/components/common/ProgressModal.tsx

@@ -146,7 +146,7 @@ export default function ProgressModal({
       className="max-w-lg"
       showCloseButton={status === 'completed' || status === 'error'}
     >
-      <div className="p-6">
+      <div className="p-6 min-h-[200px]">
         {/* Header */}
         <div className="flex items-start gap-4 mb-6">
           <div className="flex-shrink-0 mt-1">{getStatusIcon()}</div>