usePrefersReducedMotion assumes window exists

[gupta-8]

Bug

Problem

The hook accesses window.matchMedia inside an effect without checking whether window exists.

Optional chaining does not prevent a crash when window itself is undefined.

Impact

• Runtime error in SSR environments.
• Reduced portability and testability.

Location

• src/utils/usePrefersReducedMotion.ts

Suggested Fix

• Add a guard at the top of the effect:
  • Exit early if typeof window === "undefined".
• Then safely use window.matchMedia(...).