feat: Implement core application structure, AI extraction, persistence, and Telegram bot modules with updated configuration and dependencies.

app/integrations/exporters.py

@@ -0,0 +1,23 @@
+"""
+Functions for exporting data to other formats or systems (e.g., CSV, Google Sheets).
+"""
+import csv
+import io
+from typing import List
+from app.schema.base import FinalExpense
+
+def export_to_csv(expenses: List[FinalExpense]) -> str:
+    """
+    Exports a list of expenses to a CSV formatted string.
+    """
+    output = io.StringIO()
+    writer = csv.writer(output)
+
+    # Write header
+    writer.writerow(FinalExpense.__fields__.keys())
+
+    # Write data
+    for expense in expenses:
+        writer.writerow(expense.dict().values())
+
+    return output.getvalue()