Fix ProGuard Obfuscation Issues

[ghsdh3409]

Problem

• Customer apps using Monetai SDK with ProGuard/R8 obfuscation enabled were experiencing HTTP 400 errors during API calls.
• The issue occurred because field names in JSON requests were being obfuscated from proper names (e.g., sdkKey, userId) to single letters (e.g., a, b, c), causing the server to reject requests.

Solution

• Added consumer-rules.pro - Automatically protects Monetai SDK from obfuscation in customer apps
• Zero customer configuration - No ProGuard rules needed in customer apps

Benefits

• Automatic protection - Works out of the box
• No breaking changes - Backward compatible