Stop tracking data/ and images/ to preserve Plesk production data

Git pushes now only update code (html/js/php/css), not data or images.
Production users, posts, and uploaded images persist on Plesk.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

data/users.json

@@ -1,34 +0,0 @@
-[
-  {
-    "id": "user_1772963315_3561",
-    "nickname": "testi2",
-    "email": "",
-    "password": "$2y$12$bZbn25YZ6ztn5iWnDFn/3O8bx1H3fIGaFizoQhkVH3O/tLykZYrj2",
-    "likes": [
-      "pancakes",
-      "bolognese",
-      "knitting_scarf"
-    ],
-    "created": "2026-03-08"
-  },
-  {
-    "id": "user_1772963589_6366",
-    "nickname": "testi3",
-    "email": "",
-    "password": "$2y$12$D2.i04nYx4ZR6v/zobDkuutnkKH1dAMBlvnrIL4bZdSih8FXiemkq",
-    "likes": [
-      "pancakes",
-      "bolognese",
-      "knitting_scarf"
-    ],
-    "created": "2026-03-08"
-  },
-  {
-    "id": "user_1772970052_8447",
-    "nickname": "Sokerisulkakynä",
-    "email": "",
-    "password": "$2y$12$2xGWeIqsNWsJBjvnSWptqOKqwWo5V9xzJ2wcU.KaDZqo/QHNR04hG",
-    "likes": [],
-    "created": "2026-03-08"
-  }
-]