feat(Tooltip): add boundary prop to hide tooltip when it escapes an element
Adds an optional 'boundary' prop to useTooltip/Tooltip that activates
FloatingUI's 'hide' middleware with strategy='escaped'. When the tooltip
would overflow the boundary, it gets the 'invisible' class (clip-path:
inset(50%)) so it remains in the DOM for screen readers but is visually
hidden. The boundary is also passed to the 'flip' middleware so the
initial placement is more likely to stay inside it.
This lets consumers like Element Web keep the 'Expand map' tooltip on
location messages from overlapping the message composer at the bottom
of the timeline.