fix(popover): split the wheel-shim opt-in from the scroll-container styling

Two fixes on top of the reviewer's round.

**The reviewer's change, kept.** `resolvePopoverScroller` no longer falls back to
the content element unconditionally; it must match the overflow test like any
other candidate. The reviewer flagged that this could break the existing opted-in
popovers, so I checked: `.popover-scroll-content` sets `overflow-y: auto`
(main.css:601-607), so every one of them still resolves. The test needs an inline
style only because happy-dom does not apply the stylesheet -- noted in the test so
nobody reads it as a production concern.

**A bug of mine the review did not reach.** Opting the cleanup Filters panel in via
`popover-scroll-content` would also have applied that class's
`max-height: min(15rem, ...)`, crushing the panel's 471px flex column to 240px.
The class conflates 'style me as a scroll container' with 'run the wheel shim', and
a popover that manages its own layout needs only the second.

So the shim now accepts `popover-wheel-scroll` as a styling-free marker, and the
Filters panel uses that. `popover-scroll-content` keeps implying it, so no existing
caller changes.

src/renderer/src/components/ui/popover-wheel-scroll.test.tsx

@@ -77,18 +77,22 @@ describe('PopoverContent wheel shim', () => {
     renderPopover('popover-scroll-content', true)
     const content = document.querySelector<HTMLElement>('[data-slot="popover-content"]')!
     const viewport = document.querySelector<HTMLElement>('[data-testid="viewport"]')!
-    makeScrollable(content, 400, 400)
+    makeScrollable(content, 800, 400)
     makeScrollable(viewport, 1000, 400)
 
     wheel(document.querySelector<HTMLElement>('[data-testid="inner"]')!, 120)
     flushFrames()
 
     expect(viewport.scrollTop).toBe(120)
+    expect(content.scrollTop).toBe(0)
   })
 
   it('still scrolls the content itself when it is the scroller', () => {
     renderPopover('popover-scroll-content', false)
     const content = document.querySelector<HTMLElement>('[data-slot="popover-content"]')!
+    // Inline because happy-dom does not apply the stylesheet; in the app
+    // `.popover-scroll-content` already sets `overflow-y: auto` (main.css).
+    content.style.overflowY = 'auto'
     makeScrollable(content, 1000, 400)
 
     wheel(document.querySelector<HTMLElement>('[data-testid="inner"]')!, 120)
@@ -107,4 +111,55 @@ describe('PopoverContent wheel shim', () => {
 
     expect(viewport.scrollTop).toBe(0)
   })
+
+  it('ignores vertically clipped elements and horizontal-only scrollers', () => {
+    renderPopover('popover-scroll-content', true)
+    const content = document.querySelector<HTMLElement>('[data-slot="popover-content"]')!
+    const viewport = document.querySelector<HTMLElement>('[data-testid="viewport"]')!
+    content.style.overflowY = 'hidden'
+    viewport.style.overflowY = 'hidden'
+    viewport.style.overflowX = 'auto'
+    makeScrollable(content, 1000, 400)
+    makeScrollable(viewport, 1000, 400)
+    Object.defineProperty(viewport, 'scrollWidth', { value: 1000, configurable: true })
+    Object.defineProperty(viewport, 'clientWidth', { value: 400, configurable: true })
+
+    wheel(document.querySelector<HTMLElement>('[data-testid="inner"]')!, 120)
+    flushFrames()
+
+    expect(content.scrollTop).toBe(0)
+    expect(viewport.scrollTop).toBe(0)
+  })
+
+  it('does nothing when no element in the target chain can scroll', () => {
+    renderPopover('popover-scroll-content', true)
+    const content = document.querySelector<HTMLElement>('[data-slot="popover-content"]')!
+    const viewport = document.querySelector<HTMLElement>('[data-testid="viewport"]')!
+    content.style.overflowY = 'hidden'
+    viewport.style.overflowY = 'hidden'
+    makeScrollable(content, 1000, 400)
+    makeScrollable(viewport, 1000, 400)
+
+    wheel(document.querySelector<HTMLElement>('[data-testid="inner"]')!, 120)
+    flushFrames()
+
+    expect(content.scrollTop).toBe(0)
+    expect(viewport.scrollTop).toBe(0)
+  })
+
+  it('runs for the shim-only marker, which carries no styling', () => {
+    // The workspace-cleanup Filters panel needs the wheel shim but must NOT inherit
+    // `.popover-scroll-content`'s 15rem max-height, which would crush its 471px column.
+    renderPopover('popover-wheel-scroll', true)
+    const content = document.querySelector<HTMLElement>('[data-slot="popover-content"]')!
+    const viewport = document.querySelector<HTMLElement>('[data-testid="viewport"]')!
+    viewport.style.overflowY = 'auto'
+    makeScrollable(content, 400, 400)
+    makeScrollable(viewport, 1000, 400)
+
+    wheel(document.querySelector<HTMLElement>('[data-testid="inner"]')!, 120)
+    flushFrames()
+
+    expect(viewport.scrollTop).toBe(120)
+  })
 })

src/renderer/src/components/ui/popover.tsx

@@ -33,7 +33,7 @@ function resolvePopoverScroller(target: EventTarget | null, content: HTMLElement
     }
     node = node.parentNode
   }
-  return content.scrollHeight > content.clientHeight ? content : null
+  return null
 }
 
 function PopoverContent({
@@ -74,7 +74,14 @@ function PopoverContent({
       }
 
       const content = event.currentTarget
-      if (!content.classList.contains('popover-scroll-content')) {
+      // Why two markers: `popover-scroll-content` also imposes a 15rem max-height and its
+      // own overflow, which a popover that manages its own layout (a fixed-height flex
+      // column over a pinned footer) must not inherit. `popover-wheel-scroll` opts into
+      // the shim alone.
+      if (
+        !content.classList.contains('popover-scroll-content') &&
+        !content.classList.contains('popover-wheel-scroll')
+      ) {
         return
       }
 

src/renderer/src/components/workspace-cleanup/workspace-cleanup-filter-bar.tsx

@@ -70,10 +70,12 @@ export function WorkspaceCleanupFilterBar({
         <PopoverContent
           align="end"
           sideOffset={6}
-          // Why popover-scroll-content: this popover portals outside the dialog subtree,
-          // so react-remove-scroll's scroll-lock cancels wheel here and only the
-          // scrollbar drag worked. The class opts into the wheel shim.
-          className="popover-scroll-content flex h-[min(471px,var(--radix-popover-content-available-height))] w-[320px] flex-col p-0"
+          // Why popover-wheel-scroll and not popover-scroll-content: this popover portals
+          // outside the dialog subtree, so react-remove-scroll cancels wheel here and only
+          // the scrollbar drag worked. It needs the shim but not the styling half --
+          // popover-scroll-content caps height at 15rem, which would crush this panel's
+          // 471px flex column.
+          className="popover-wheel-scroll flex h-[min(471px,var(--radix-popover-content-available-height))] w-[320px] flex-col p-0"
         >
           {/* 471px preserves the 420px facet viewport plus the fixed footer at full height. */}
           <ScrollArea className="min-h-0 flex-1">