[FEATURE] Dynamic Pricing Information

Is your feature request related to a problem? Please describe.

The current static pricing system in MODEL_REGISTRY has several critical issues:

1. Outdated pricing data - Many models have incorrect or obsolete pricing information
2. Phantom models - Non-existent models like openai/gpt-4.5-preview with pricing ($75/1M) that cause user errors
3. Limited model coverage - Only 25 static models vs 320+ available on OpenRouter
4. Manual maintenance - Requires code updates for every pricing change or new model
5. No real-time validation - Users get confused by models that don't actually exist

Example: openai/gpt-4.5-preview shows expensive static pricing but the model was removed by OpenAI.

Describe the solution you'd like

Implement a hybrid dynamic pricing system that:

1. Primary: Fetch real-time pricing from OpenRouter API (320+ models)
2. Fallback: Use static pricing when API is unavailable
3. Performance: 3-second timeout with 24-hour caching and auto-refresh
4. Extended support: Handle advanced pricing (image, cache, reasoning costs)
5. Agent integration: Automatically initialize dynamic pricing when agents start

Key features:

• Real-time model availability detection
• Comprehensive fuzzy matching for model names
• Extended pricing fields (image: $0.024, cache_read: $1.5/1M)
• Silent operation (no debug prints)
• Thread-safe caching with automatic refresh