fix(editor): cap the function-tree category grid so the item list stays reachable

[Aymericr]

The defensive fix I offered @yanrin13 in #562. That issue's bug is in our hosted RoomsPanel, which isn't in this repo — but the same layout shape exists here and is reachable.

The shape

FunctionTreePanel renders root categories as grid shrink-0 grid-cols-5 with aspect-square tiles (function-tree-panel.tsx:124), above the only scroller in the panel:

<div className="min-h-0 flex-1 overflow-y-auto p-3">   // :240

Column count is fixed at 5, so row count is ceil(functionTree.length / 5) and each row is as tall as it is wide. Because the header is shrink-0, flex-1 on the list resolves toward zero as the header grows — past roughly 20 categories the list is off-panel with no way to scroll it back.

Why this one and not its sibling

The other header in this panel family, furnishTools (items-panel/index.tsx:197), is the same shrink-0 pattern but is a static 6-item array in ui/action-menu/furnish-tools.tsx — bounded by code, so it can't reach this state. I left it alone.

functionTree is different: it's a prop, supplied by the embedder (items-panel/index.tsx:60, functionTree: FunctionTreeNode[]), so its length crosses the embedding boundary and this package can't bound it. That's exactly the invariant #562 broke — a header whose height is driven by data rather than by code.

Fix

-<div className="grid shrink-0 grid-cols-5 gap-1.5 border-border/70 border-b p-2">
+<div className="grid max-h-[40%] shrink-0 grid-cols-5 gap-1.5 overflow-y-auto border-border/70 border-b p-2">

The header degrades to scrolling instead of consuming the panel. No visual change at today's category counts — max-h only engages once the grid would exceed 40% of panel height.

One note: I first wrote this with subtle-scrollbar, the class the hosted app and several components here use alongside overflow-y-auto. It has no definition anywhere in this repo — it comes from the hosted app's stylesheet — so including it would have been a silent no-op. Dropped it; the scrollbar is the browser default, consistent with other open-source-side scrollers.

Gates

check 1600 files clean · check-types 9/9 · test 12/12

🤖 Generated with Claude Code

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Note

Low Risk
Small layout/CSS fix in the items sidebar with no auth, data, or API changes.

Overview
Caps the embedder-supplied root category tile grid in FunctionTreePanel so a large functionTree cannot grow the header past the panel and squeeze the item list to zero height.

The root grid gains max-h-[40%] and overflow-y-auto, so extra categories scroll inside the header instead of stealing space from the only main scroller below. A comment documents that functionTree is unbounded and aspect-square tiles make row count scale with data.

No behavior change at typical category counts—the limit only applies when the grid would exceed ~40% of panel height.

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