fix: disable SSO auth header injection for main permission

Technitium manages its own authentication and does not integrate with
YunoHost SSO. When auth_header is enabled (the default), SSOwat injects
an 'Authorization: Basic' header containing the YunoHost user's
credentials into every proxied request. Technitium receives this header,
attempts to authenticate the YunoHost user against its own user database,
fails silently, and redirects back to its login page — creating a login
loop that affects users who are logged into YunoHost SSO.

Setting auth_header = false prevents SSOwat from injecting credentials,
allowing Technitium to handle authentication with its own login form.

The app already correctly declares sso = false and ldap = false, making
auth_header = false the consistent and expected setting.

manifest.toml

@@ -77,6 +77,7 @@ ram.runtime = "50M"
 
     [resources.permissions]
     main.url = "/"
+    main.auth_header = false
 
     [resources.ports]
     main.default = 5380