v0.6.1: remove duplicate is_valid_email from app.py (re now lives in helpers)

app.py

@@ -494,15 +494,6 @@ def admin_login():
     return render_template('admin/login.html')
 
 
-def is_valid_email(email):
-    """Return True if the given string looks like a valid email address."""
-    if not email:
-        return False
-    # Very loose regex: local@domain.tld, no spaces, with a real TLD part.
-    pattern = r"^[^\s@]+@[^\s@]+\.[^\s@]+$"
-    return re.match(pattern, email) is not None
-
-
 @app.route('/admin/logout')
 def admin_logout():
     """Clear the admin session."""