🤖 fix: clamp right sidebar width to prevent overflow

[jaaydenh]

Summary

Prevents the workspace view from overflowing horizontally (and showing a bottom scrollbar) when the right sidebar is resized or the app window is narrowed.

Background

WorkspaceShell allows horizontal scrolling (overflow-x-auto). With ChatPane having a desktop minimum width (min-w-96 = 384px) and the right sidebar using a fixed pixel width, resizing could make the combined widths exceed the available container width.

Implementation

• Clamp the right sidebar’s effective max width to: min(ABS_MAX, max(MIN, containerWidth - chatMinWidth)).
  • Uses useResizeObserver() on the WorkspaceShell root element.
  • Avoids rewriting the stored width in stacked (flex-col) mode.
• Add a defensive maxWidth: "100%" to the right sidebar container so a persisted width can’t overflow narrow/stacked layouts.
• Add a UI integration test that asserts the sidebar cannot be resized beyond the effective max.

Validation

• make static-check

Risks

Low-to-moderate: affects workspace layout sizing. The clamp has a safe fallback when container width is unknown.

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