Add UIZZE to Product.md

[samuelbushi]

Product

Adds UIZZE to the community product directory as a Design / Developer Tools resource.

UIZZE's public Web and iOS UI-reference catalog is free to browse. Paid agent tools are available when coding-agent workflows need them. The entry links directly to the existing free-Mobbin-alternative research page.

Checklist

• I checked that this product is not already listed.
• I used the row template with all required columns.
• I verified the HTTPS link returns HTTP 200 and is indexable with a self-canonical URL.
• I kept the one-line description neutral and concise.
• I used no referral or tracking link.
• git diff --check passes and Product.md is the only changed file.