Add a TagField control for Web projects

Add a designer-visible TagField control to Web projects so applications can collect and edit short token-style values — recipients, keywords, labels, filter chips — the way they already can on the desktop.

The control should render entered values as removable chips alongside an inline editor, accept entry by typing, pasting, and (optionally) commas, offer optional suggestion completion, and enforce duplicate and count limits. Events when tags are added, removed, or pressed let applications react as the user edits. This would bring Web projects to parity with the desktop TagField for tagging and chip-input workflows without application authors hand-building the browser interaction.