fix: delete terraform workspace and files when deleting chat session

backend/app.py

@@ -3518,6 +3518,13 @@ async def rename_session(sid: str, req: dict = Body(...), u=Depends(current_user
 @app.delete("/api/chat/{sid}")
 async def clear_chat(sid, u=Depends(current_user)):
     with db() as c:
+        # Delete associated terraform workspaces and their files
+        ws_rows = c.execute("SELECT id FROM terraform_workspaces WHERE session_id=? AND user_id=?", (sid, u["id"])).fetchall()
+        for ws in ws_rows:
+            wdir = TERRAFORM_DIR / ws["id"]
+            if wdir.exists():
+                shutil.rmtree(wdir, ignore_errors=True)
+        c.execute("DELETE FROM terraform_workspaces WHERE session_id=? AND user_id=?", (sid, u["id"]))
         c.execute("DELETE FROM chat_messages WHERE session_id=? AND user_id=?", (sid, u["id"]))
         c.execute("DELETE FROM chat_sessions WHERE id=? AND user_id=?", (sid, u["id"]))
     return {"ok": True}