feat(keys): auto-generate entity keys and remove manual key input from admin create forms

backend/app/core/keygen.py

@@ -0,0 +1,9 @@
+from datetime import datetime
+import time
+
+
+def generate_key(prefix: str, salt: int = 0) -> str:
+    date_str = datetime.now().strftime("%Y%m%d")
+    tail = (int(time.time() * 1000) + salt) % 10000
+    return f"{prefix}{date_str}X{tail:04d}"
+