FE-1515: Give sidebar list labels the full row width until the row menu shows

[kube]

Copy of #9367 which cannot be re-opened.

🌟 What is the purpose of this PR?

Left-sidebar list items cropped inconsistently. Rows with a row menu always reserved space for the hidden "More options" button (it was revealed by animating opacity, which keeps its layout size), so those lists wrapped labels ~20px early — while lists without menus used the full width. And items rendering a name with a subtitle (e.g. parameters) escaped the row's ellipsis and clipped hard, while plain-text items showed "…".

Labels now take the full row width with a consistent ellipsis, and only shrink while the row is hovered (or its menu is open), when the button actually appears.

Before — space reserved for the hidden button, and name/subtitle lines hard-clip without an ellipsis:

After — full-width labels, consistent "…" truncation (same net, same 200px sidebar):

🔗 Related links

• FE-1515

🚫 Blocked by

• FE-1512: Place arc weight labels on the Adaptive Bezier curve #9354 — stacked on claude/fe-1512-adaptive-bezier-label-midpoint; only the last commit belongs to this PR until the stack below merges.

🔍 What does this change?

• filterable-list-sub-view.tsx hides [data-row-action] with display: none instead of opacity: 0, revealing it on row hover or while its menu is open — the hidden button no longer occupies layout.
• listItemNameStyle applies its truncation (nowrap, hidden overflow, ellipsis) to nested item lines as well, so name + subtitle renderers truncate like plain-text ones.

Pre-Merge Checklist 🚀

🚢 Has this modified a publishable library?

This PR:

• modifies an npm-publishable library and I have added a changeset file(s)

📜 Does this require a change to the docs?

The changes in this PR:

• are internal and do not require a docs change

The user guide does not describe row-menu reveal behaviour.

🕸️ Does this require a change to the Turbo Graph?

The changes in this PR:

• do not affect the execution graph

⚠️ Known issues

• The 150ms fade/slide reveal animation is gone — display cannot transition, so the button appears instantly. A @starting-style fade can be added later if the pop feels abrupt.
• While hidden, the button is no longer in the tab order (display: none). Previously it was tab-focusable but invisible, which was not meaningfully more accessible.

🛡 What tests cover this?

• None — CSS-only. Verified in the running app: button computes display: none by default and the label content spans the full row (244px of a 256px row); forcing the menu-open state (the same rule as :hover) shows the 20px button and shrinks the content to 224px; nested name and <pre> subtitle lines compute nowrap / ellipsis / hidden.

❓ How to test this?

1. yarn workspace @hashintel/petrinaut dev, open a story with parameters (e.g. Handle Spike With Sir), narrow the left sidebar.
2. Long labels truncate with "…" and reach the row's right edge; name and subtitle lines truncate alike.
3. Hover a row: the "⋯" button appears and the label shortens; unhover with the menu open: the button stays.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated (UTC)
hash	Ready	Preview	Aug 27, 2026 1:37pm
petrinaut	Ready	Preview	Aug 27, 2026 1:37pm
petrinaut-docs	Ready	Preview	Aug 27, 2026 1:37pm

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
hashdotdesign-tokens	Ignored	Preview	Aug 27, 2026 1:37pm

[cursor]

PR Summary

Low Risk
CSS-only layout and truncation in a shared sidebar list component; no auth, data, or API changes. Trade-off is instant menu button reveal and display: none removing the action from tab order while hidden.

Overview
Left sidebar filterable list rows no longer reserve horizontal space for the hidden “More options” control. The row action is hidden with display: none and shown on row hover or while the menu is open (display: flex), so labels use the full row width until the button actually appears. The previous opacity-based reveal (and its slide animation) is removed.

Label truncation is tightened: the name cell gets minWidth: 0 for flex shrinking, and ellipsis/nowrap rules apply to nested content from renderItem (e.g. name + subtitle) so those lines match plain-text items instead of hard-clipping.

Includes a patch changeset for @hashintel/petrinaut.

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