FreshScan AI v1.3.0 - Leaderboards & Badges

✨ New Features

• feat: implement global dark/light mode toggle by @atmihaa-06 in #41 #50
• Added global Vendor Trust Score Leaderboard by @Aharshi3614 in #64
• Added High/Low Confidence badges to analysis results by @aditikhushi81-cpu in #51

🛠️ Backend & Testing

• Added 100% branch coverage and robust validation for grade derivation by @BHOGALA-SRIKA in #63