feat: Initialize frontend with React, Vite, and Tailwind CSS

- Set up main entry point for React application.
- Create About, Home, NotFound, Privacy, and Terms pages with SEO support.
- Implement API service for file uploads and task management.
- Add global styles using Tailwind CSS.
- Create utility functions for SEO and text processing.
- Configure Vite for development and production builds.
- Set up Nginx configuration for serving frontend and backend.
- Add scripts for cleanup of expired files and sitemap generation.
- Implement deployment script for production environment.

backend/app/routes/tasks.py

@@ -0,0 +1,39 @@
+"""Task status polling endpoint."""
+from flask import Blueprint, jsonify
+from celery.result import AsyncResult
+
+from app.extensions import celery
+
+tasks_bp = Blueprint("tasks", __name__)
+
+
+@tasks_bp.route("/<task_id>/status", methods=["GET"])
+def get_task_status(task_id: str):
+    """
+    Get the status of an async task.
+
+    Returns:
+        JSON with task state and result (if completed)
+    """
+    result = AsyncResult(task_id, app=celery)
+
+    response = {
+        "task_id": task_id,
+        "state": result.state,
+    }
+
+    if result.state == "PENDING":
+        response["progress"] = "Task is waiting in queue..."
+
+    elif result.state == "PROCESSING":
+        meta = result.info or {}
+        response["progress"] = meta.get("step", "Processing...")
+
+    elif result.state == "SUCCESS":
+        task_result = result.result or {}
+        response["result"] = task_result
+
+    elif result.state == "FAILURE":
+        response["error"] = str(result.info) if result.info else "Task failed."
+
+    return jsonify(response)