Tailscale serve support (#2126)

Ensure we can serve the app from multiple hosts without breaking links.
* Switch unnecessary full URLs to paths
* Drop default host/port URL options for controllers

Shell 1
```bash
bin/dev
```

Shell 2
```bash
tailscale serve http://fizzy.localhost:3006
```

app/controllers/concerns/authentication.rb

@@ -38,7 +38,7 @@ module Authentication
 
     def require_account
       unless Current.account.present?
-        redirect_to main_app.session_menu_url(script_name: nil)
+        redirect_to main_app.session_menu_path(script_name: nil)
       end
     end
 
@@ -125,7 +125,7 @@ module Authentication
       serve_development_magic_link(magic_link)
       session[:email_address_pending_authentication] = magic_link.identity.email_address if magic_link
       session[:return_to_after_authenticating] = return_to if return_to
-      redirect_to main_app.session_magic_link_url(script_name: nil)
+      redirect_to main_app.session_magic_link_path(script_name: nil)
     end
 
     def serve_development_magic_link(magic_link)

app/controllers/concerns/authorization.rb

@@ -26,7 +26,7 @@ module Authorization
     end
 
     def ensure_can_access_account
-      redirect_to session_menu_url(script_name: nil) if Current.user.blank? || !Current.user.active?
+      redirect_to session_menu_path(script_name: nil) if Current.user.blank? || !Current.user.active?
     end
 
     def redirect_existing_user

config/environments/development.rb

@@ -85,9 +85,14 @@ Rails.application.configure do
     config.action_mailer.raise_delivery_errors = false
   end
 
-  config.hosts = %w[ fizzy.localhost localhost 127.0.0.1 ] + [ /^fizzy-\d+(:\d+)$/ ]
+  config.hosts = [
+    "fizzy.localhost",
+    "localhost",
+    "127.0.0.1",
+    /^fizzy-\d+(:\d+)?$/, # review apps: fizzy-123:3000
+    /\.ts\.net$/         # tailscale serve: hostname.tail1234.ts.net
+  ]
 
-  # Set host to be used by links generated in mailer and notification view templates.
-  config.action_controller.default_url_options = { host: config.hosts.first, port: 3006 }
-  config.action_mailer.default_url_options     = { host: config.hosts.first, port: 3006 }
+  # Canonical host for mailer URLs (emails always link here, not personal Tailscale URLs)
+  config.action_mailer.default_url_options = { host: "#{config.hosts.first}:3006" }
 end