Picking a file loads its current content to edit in place

proposed_yaml binds to the file select: the selected file's content
fetches through Gitea's contents API (base64-decoded by the jq
filter) and lands in the editor. On-site contributions no longer
start from a blank box.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -158,7 +158,10 @@ Question            id (doubles as the URL path), name, description,
                     (Iconify name, e.g. lucide:star), requirements[],
                     resource
       Requirement   name, label, type, optional, multiple, placeholder,
-                    accept (file), resource + id_field (select options)
+                    accept (file), resource + id_field (select options),
+                    bind {field, param, resource} (load this field's
+                    value from a resource whenever the named sibling
+                    changes - {param} templates into a url source's path)
       ResourceSpec  source (kv | gitea_starred | gitea_org_repos | url),
                     key, public, requires_group, transitions[{from, to, label}],
                     jq (reshape filter)