feat/pane-expansion : Add expansion anchors and enforce 250dp minimum…

[prateekbatra-g]

Improves the adaptive Master-Detail layout (CahierNavigationSuite) resizing behavior on large-screen devices. It adds snap-to anchors and guarantees that neither the list nor the detail pane is squished past legibility during resizing.
Key Changes

• Pane Expansion Anchors: Added snap positions in rememberPaneExpansionState at 0% (collapsed), 25% (minimum snap), 50% (half split), and 100% (expanded).
• 250dp Minimum Width: Enforced a 250.dp (MinPaneWidth) constraint using a custom .layout modifier on both listPane and detailPane.
• Refactoring: Extracted MinPaneWidth as a clean, file-level constant to prevent magic numbers and keep Composable signatures lightweight.

Before	After

[gemini-code-assist]

Code Review

This pull request configures pane expansion anchors for the list-detail scaffold, applies a custom layout modifier to enforce a minimum width on both the list and detail panes, and adjusts z-indices and elevations for proper layering. The reviewer suggests extracting the duplicated layout logic into a reusable Modifier extension function that handles clipping and collapsed states to prevent visual bleeding. Additionally, the reviewer highlights a discrepancy between the defined snapping anchors and the initial pane proportion of 0.3f, which could cause a jumpy user experience.

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[cka-dev]

This is a nice update.

Only one thing: can you run the screenshot tests and make sure they are passing.
I think the change is affecting some of the existing screenshot tests.

[cka-dev]

lgtm