[grade=B] feat(auth): onboard missing credentials into encrypted vault

dashcaddy-installer/src/main/caddyfile-generator.js

@@ -51,10 +51,15 @@ class CaddyfileGenerator {
   _authSnippet(apiPort) {
     return `# DashCaddy SSO auth snippet
 (dashcaddy_auth) {
-  forward_auth localhost:${apiPort} {
+  @needsAuth not path /dashcaddy-sso
+  forward_auth @needsAuth localhost:${apiPort} {
     uri /api/v1/auth/gate/{args[0]}
     copy_headers Authorization X-Api-Key X-App-Cookie X-Emby-Token X-Plex-Token
   }
+  handle /dashcaddy-sso {
+    rewrite * /api/v1/auth/sso-exchange
+    reverse_proxy localhost:${apiPort}
+  }
 }
 `;
   }