refactor: update application code to use unified configuration

- Update App.tsx to use getAppConfig() instead of import.meta.env
- Update email templates to use getAppConfig() for base URL
- Update database strategy to use getDatabaseConfig() function
- Update mailgun service to use getter functions
- Remove direct unified config imports in favor of functions
- Ensure consistent configuration access throughout codebase

services/mailgun.service.ts

@@ -4,7 +4,7 @@
  */
 
 import { getMailgunConfig, type MailgunConfig } from './mailgun.config';
-import { unifiedConfig } from '../config/unified.config';
+import { getAppConfig } from '../config/unified.config';
 
 interface EmailTemplate {
   subject: string;
@@ -139,13 +139,13 @@ export class MailgunService {
   }
 
   async sendVerificationEmail(email: string, token: string): Promise<boolean> {
-    const verificationUrl = `${unifiedConfig.app.baseUrl}/verify-email?token=${token}`;
+    const verificationUrl = `${getAppConfig().baseUrl}/verify-email?token=${token}`;
     const template = this.getVerificationEmailTemplate(verificationUrl);
     return this.sendEmail(email, template);
   }
 
   async sendPasswordResetEmail(email: string, token: string): Promise<boolean> {
-    const resetUrl = `${unifiedConfig.app.baseUrl}/reset-password?token=${token}`;
+    const resetUrl = `${getAppConfig().baseUrl}/reset-password?token=${token}`;
     const template = this.getPasswordResetEmailTemplate(resetUrl);
     return this.sendEmail(email, template);
   }