sources: add image_url?, page_url?, and profile_url? methods.

Add methods to Source::URL for determining whether a URL is an image
URL, a page URL, or a profile URL.

Also add more source URL tests and fix various URL parsing bugs.

app/logical/source/url/foundation.rb

@@ -9,7 +9,7 @@
 # * https://foundation.app/collection/kgfgen
 
 class Source::URL::Foundation < Source::URL
-  attr_reader :username, :token_id, :work_id, :hash
+  attr_reader :username, :user_id, :token_id, :work_id, :hash
 
   IMAGE_HOSTS = %w[assets.foundation.app f8n-ipfs-production.imgix.net f8n-production-collection-assets.imgix.net d2ybmb80bbm9ts.cloudfront.net]
 
@@ -69,6 +69,10 @@ class Source::URL::Foundation < Source::URL
     end
   end
 
+  def image_url?
+    host.in?(IMAGE_HOSTS)
+  end
+
   def profile_url
     if username.present?
       "https://foundation.app/@#{username}"