Allow Stripe checkout in CSP form-action directive

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: barckcode

src/layouts/Base.astro

@@ -34,7 +34,7 @@ const {
     <meta name="twitter:description" content={description} />
     <meta
       http-equiv="Content-Security-Policy"
-      content="default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com; img-src 'self' data:; connect-src 'self'; frame-src 'none'; object-src 'none'; base-uri 'self'; form-action 'self';"
+      content="default-src 'self'; script-src 'self' 'unsafe-inline'; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; font-src 'self' https://fonts.gstatic.com; img-src 'self' data:; connect-src 'self'; frame-src 'none'; object-src 'none'; base-uri 'self'; form-action 'self' https://checkout.stripe.com;"
     />
     <title>{title}</title>
   </head>