feat: safe compare ids

[doc-han]

Description

This PR [adds/changes/fixes]... (A description of your work goes here.)

Closes #__

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[github-actions]

Security Review ✅

• S0 (project scoping): N/A — change is a client-side null-safe sort comparator in useUnsavedChanges.ts:71,83; no queries or web-layer entrypoints touched.
• S1 (authorization): N/A — no new handlers, controllers, or LiveView events introduced.
• S2 (audit trail): N/A — no writes to config resources; the diff only affects an in-memory sort for change detection.