flora-6: update Caddyfile, add missing pub.solar

config for www and mastodon well-known redirect

hosts/flora-6/caddy.nix

@@ -15,8 +15,34 @@
           output discard
         '';
         extraConfig = ''
-          root * /srv/www/pub.solar/
+          # PubSolarOS images
+          handle /os/download/* {
+            root * /srv/www
+            file_server /os/download/* browse
+          }
+          # serve base domain pub.solar for mastodon.pub.solar
+          # https://masto.host/mastodon-usernames-different-from-the-domain-used-for-installation/
+          handle /.well-known/host-meta {
+            redir https://mastodon.pub.solar{uri}
+          }
+          # pub.solar website
+          handle {
+            root * /srv/www/pub.solar
+            try_files {path}.html {path}
             file_server
+          }
+          # minimal error handling, respond with status code and text
+          handle_errors {
+            respond "{http.error.status_code} {http.error.status_text}"
+          }
+        '';
+      };
+      "www.pub.solar" = {
+        logFormat = lib.mkForce ''
+          output discard
+        '';
+        extraConfig = ''
+          redir https://pub.solar{uri}
         '';
       };
       "auth.pub.solar" = {