chore(tests): organize test scripts and beautify account creation email

- Moved scattered Python test scripts from root and 'admin/development/' to 'tests/'.
- Beautified the HTML email body for account creation links in 'app/methods/person_methods.py' with a modern responsive design.

tests/check_db_schema.py

@@ -0,0 +1,13 @@
+from app.db_sql import db
+from sqlalchemy import text
+
+def check_columns():
+    try:
+        result = db.execute(text("DESCRIBE account"))
+        columns = [row[0] for row in result.fetchall()]
+        print(f"Columns in 'account': {columns}")
+    except Exception as e:
+        print(f"Error describing 'account': {e}")
+
+if __name__ == "__main__":
+    check_columns()