fix(Tooltip): identity-check mouseout target and track node position on view changes

[w8r]

Problem

Two bugs in the hover-triggered <Tooltip> component:

1. Premature close on foreign mouseout

The mouseout listener was firing for any node/edge mouseout, not just the element that triggered the mouseover. Rapidly moving between two adjacent nodes would cause a foreign mouseout to immediately close the tooltip.

Root cause: the handler only checked evt.target?.isNode (correct type) but never verified evt.target === storedTarget (correct identity).

2. Stale tooltip position after node drag or zoom

The tooltip position was computed once at hover time and never updated when:

• the user drags the node to a new location, or
• the user zooms (which changes the radius-based offset in graph coordinates).

Fix

Identity check: Mirror target state into a targetRef so the stable event-handler closure can always read the current value. Gate hideTooltip() on evt.target === targetRef.current.

Position tracking: Declare a hoisted onViewUpdate callback (registered on nodesDragProgress and idle) that reads the node's current graph position via node.getPosition(), recomputes the zoom-adjusted offset, calls layer.setPosition(), and triggers the existing overflow re-check by calling setPoint().

A pointRef is added alongside targetRef so both callbacks can read current values from stable closures without being re-registered on every hover change.

Checklist

• TypeScript typecheck passes (npm run typecheck)
• Prettier + oxlint pass (husky pre-commit hooks ran clean)
• No changes to public API or types