Update API specifications with fern api update

[github-actions]

Update API specifications by running fern api update.

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Note

Medium Risk
OpenAPI contract changes add a new connection field and reject empty-string parentId values, which may affect API clients and server validation behavior.

Overview
Updates openapi.json (Fern API sync) to document new diagram connection routing and tighter model object ID rules.

Diagram connections (DiagramConnection, DiagramConnectionPartial, DiagramConnectionRequired) now expose an optional breakpoints array (up to 100 {x, y} points). The spec states breakpoints apply only to square line shapes, are rejected for other shapes, and must form a valid orthogonal path (right-angle segments, no diagonals or duplicate points).

Model objects gain parentId minLength: 1 on the affected create/update schemas, so non-null parent IDs must be non-empty strings while null remains valid for root-level objects.

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