Unsupported legacy internals

Pressundo does not promise drop-in emulation of every undocumented Vafpress internal. Examples that should be migrated include:

• Direct subclassing/use of internal VP_Control_Field_* classes.
• Arbitrary custom dependency/binding callbacks expecting old AJAX execution.
• Old Vafpress views/assets used directly.
• Undocumented WPAlchemy internals beyond the audited common facade.
• The obsolete TinyMCE/AJAX runtime of the old shortcode generator.

The safe VP_ShortcodeGenerator facade exists for construction/pool/tag discovery, but the obsolete runtime is intentionally not resurrected.