Add weapon data

public/data/weapons/holy-guns-kallen.json

@@ -0,0 +1,13 @@
+{
+  "id": "holy-guns-kallen",
+  "name": "Holy Guns - Kallen",
+  "atk": 183,
+  "crt": 10,
+  "rarity": 4,
+  "skills": [
+    {
+      "name": "Sacred Guardian",
+      "description": "When attacked, character absorbs 40% of incoming DMG and unleashes Divine Impact, dealing 290% ATK of Physical DMG to surrounding enemies and slowing their ATK Speed by 75% for 4.5s. Sacred Guardian can be triggered once every 15s."
+    }
+  ]
+}