v0.2.2

Tidies the snapshot toolbar option — single object form, clearer naming.

• ToolbarOptions.snapshot is now "none" | false | null | { quality?, onClick? }
  (no more bare-preset string form). undefined ⇒ defaults (a button); any
  explicit falsy value (null / false / "none") hides it.
• Renamed the size field state → quality, and the type SnapshotLevel →
  SnapshotQuality ("native" | "low" | "medium" | "high" — "none" moved out
  to the option's union, where it belongs).
• The toolbar button live-previews the delivery while hovered: holding the modifier
  key swaps its icon to the alternate action (the tooltip is fixed — see 0.2.5). Key
  listeners are scoped to the hover only (no global churn). New ToolbarItem.onRender
  hook + exported SNAPSHOT_CLIPBOARD_ICON.