docs: add automatic form field detection to supported operations

Author: bendersej

agent-pdf/SKILL.md

@@ -123,6 +123,7 @@ With a company-specific portal:
 
 Once the user opens the editor link, they can:
 
+- Automatic detection of form fields
 - Fill form fields (text inputs, checkboxes, radio buttons, dropdowns)
 - Add free text annotations anywhere on the page
 - Draw or type signatures