Update API specifications with fern api update

[github-actions]

Update API specifications by running fern api update.

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Note

Medium Risk
Public API contract changes: new connection routing data and stricter validation that may reject empty-string parent IDs previously accepted by clients.

Overview
Regenerates OpenAPI specs to match the current Fern API surface.

Diagram connections now expose an optional breakpoints array (up to 100 {x, y} points) on DiagramConnection, DiagramConnectionPartial, and DiagramConnectionRequired. The schema documents that breakpoints apply only to square line shapes, are ignored/rejected for other shapes, and must form a valid orthogonal path (shared x/y between neighbors, no duplicates, right-angle corners only).

Model objects (ModelObjectPartial, required, and full variants) add minLength: 1 on parentId, so a non-null parent must be a non-empty string; null remains valid for root objects.

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