Deploy to Cloudflare Workers and rebrand to Diagrav

Adds Workers + static-assets configs for the app (app.diagrav.com) and a
separate marketing/landing site (diagrav.com), plus the deployment runbook
used to stand up Supabase Cloud, Google OAuth, Resend SMTP, and Cloudflare
DNS/custom domains. Renames the app from "AV Planner" to "Diagrav" to match
the new domain.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017DUU6CnxECCDeqDNYJgr5x

index.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8" />
     <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>AV Planner</title>
+    <title>Diagrav</title>
   </head>
   <body>
     <div id="root"></div>