fix(web): let the pointer reach hover cards and row menus

The workspace browser's two hover-raised popups both died on the way to
them. HoverCard closed on the first pointerleave and rendered its card
pointer-events:none, but the card sits 8px off the anchor, so every path
to it crossed ground belonging to neither. The row action menus put
closeOnPointerLeave's handler on the portaled list, so aiming back at the
... trigger that opened it, or overshooting a list edge, closed it with no
window to come back.

usePointerGrace owns one cancelable delayed close (200ms) shared by both
atoms: leaving arms it, returning cancels it. The hover card becomes
hit-testable so resting on it holds it open, and Menu moves pointer-leave
dismissal to the wrapper span, where React's enter/leave traversal makes
trigger and portaled list one region.

Both gestures are pinned in the real browser lane; each fails without the
corresponding fix.

packages/client/ui-primitives/src/HoverCard.tsx

@@ -1,18 +1,24 @@
 // HoverCard: delayed hover-preview card portaled to document.body.
 // Same portal mechanics as Menu: the wrapper span supplies the anchor rect,
 // the card is fixed-positioned at its right edge and repositions on
-// scroll/resize while open. Display-only — the card ignores pointer events
-// and closes the instant the pointer leaves the anchor (no close delay).
+// scroll/resize while open. The card is reachable: it takes pointer events,
+// and leaving the anchor only arms a grace-delayed close, so the pointer can
+// cross the 8px gap and settle on the card to read a clipped path or title.
+// The portaled card is a React child of the wrapper, so React's enter/leave
+// traversal already treats it as inside — one pair of wrapper handlers covers
+// anchor and card alike.
 
 import { useEffect, useLayoutEffect, useRef, useState } from 'react'
 import type { ReactNode } from 'react'
 import { createPortal } from 'react-dom'
+import { usePointerGrace } from './pointer-grace.ts'
 import css from './HoverCard.module.css'
 
 /**
  * Render an anchor with a hover-triggered preview card.
  * @param props.anchor - the hover target (rendered in place inside a wrapper span).
- * @param props.content - card content (display-only, no pointer interaction).
+ * @param props.content - card content; the pointer may rest on it, so it is
+ * readable and selectable, but it carries no dismissal affordance of its own.
  * @param props.openDelayMs - hover dwell before the card shows (default 500).
  * @param props.disabled - suppress opening; turning true closes an open card.
  * @returns anchor wrapper with the conditional portaled card.
@@ -29,6 +35,8 @@ export function HoverCard({ anchor, content, openDelayMs = 500, disabled = false
   const [open, setOpen] = useState(false)
   const [pos, setPos] = useState<{ left: number; top: number } | null>(null)
 
+  const { arm: armClose, cancel: cancelClose } = usePointerGrace(() => { setOpen(false) })
+
   const clearTimer = () => {
     if (timerRef.current !== null) {
       clearTimeout(timerRef.current)
@@ -40,8 +48,9 @@ export function HoverCard({ anchor, content, openDelayMs = 500, disabled = false
   useEffect(() => {
     if (!disabled) return
     clearTimer()
+    cancelClose()
     setOpen(false)
-  }, [disabled])
+  }, [disabled, cancelClose])
 
   useEffect(() => clearTimer, [])
 
@@ -91,17 +100,22 @@ export function HoverCard({ anchor, content, openDelayMs = 500, disabled = false
       className={css.root}
       onPointerEnter={() => {
         if (disabled) return
+        // Coming back inside during the grace (the gap, or the card itself)
+        // keeps the current card rather than restarting the dwell.
+        cancelClose()
+        if (open) return
         clearTimer()
         timerRef.current = setTimeout(() => { setOpen(true) }, openDelayMs)
       }}
       onPointerLeave={() => {
         clearTimer()
-        setOpen(false)
+        armClose()
       }}
       // Any press inside the anchor (row click, menu trigger) dismisses the
       // card immediately, without waiting for the owner to flip `disabled`.
       onPointerDownCapture={() => {
         clearTimer()
+        cancelClose()
         setOpen(false)
       }}
     >