feat: SMTP integration, dynamic app_settings for email, and email verification enforcement for tier upgrades

api/db/init.sql

@@ -5,6 +5,8 @@ CREATE TABLE IF NOT EXISTS users (
     email VARCHAR(255) UNIQUE NOT NULL,
     password_hash VARCHAR(255) NOT NULL,
     role VARCHAR(50) DEFAULT 'free',
+    is_email_verified BOOLEAN DEFAULT false,
+    email_verification_token VARCHAR(255),
     created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
 );