Add migration file to populate total tasks for old projects if null

src/backend/migrations/populate_total_tasks.py

@@ -0,0 +1,32 @@
+"""Populate total_tasks for old projects."""
+
+import asyncio
+
+from psycopg import AsyncConnection
+
+from app.config import settings
+
+
+async def populate_total_tasks():
+    """Populate total_tasks for all projects where it's NULL or 0."""
+    async with await AsyncConnection.connect(
+        settings.FMTM_DB_URL.unicode_string()
+    ) as db:
+        async with db.cursor() as cur:
+            sql = """
+                UPDATE projects
+                SET total_tasks = (
+                    SELECT COALESCE(MAX(project_task_index), 0)
+                    FROM public.tasks
+                    WHERE projects.id = tasks.project_id
+                )
+                WHERE total_tasks IS NULL OR total_tasks = 0;
+            """
+            await cur.execute(sql)
+            await db.commit()
+
+    print("✅ Total tasks populated successfully")
+
+
+if __name__ == "__main__":
+    asyncio.run(populate_total_tasks())