feat: enable prompt caching for all Claude models

Added supports_prompt_caching: true to all Claude models:
- claude-sonnet-4
- claude-sonnet-4.5
- claude-3-5-sonnet
- claude-3-opus
- claude-3-haiku

This enables Anthropic's prompt caching feature across all models,
significantly reducing latency and costs for repeated requests
with the same system prompts.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

ai/litellm-config.yaml

@@ -3,29 +3,36 @@ model_list:
     litellm_params:
       model: anthropic/claude-sonnet-4-20250514
       api_key: os.environ/ANTHROPIC_API_KEY
+      drop_params: true
+      supports_prompt_caching: true
 
   - model_name: claude-sonnet-4.5
     litellm_params:
       model: anthropic/claude-sonnet-4-5-20250929
       api_key: os.environ/ANTHROPIC_API_KEY
       drop_params: true
-      # Enable prompt caching for better performance
       supports_prompt_caching: true
 
   - model_name: claude-3-5-sonnet
     litellm_params:
       model: anthropic/claude-3-5-sonnet-20241022
       api_key: os.environ/ANTHROPIC_API_KEY
+      drop_params: true
+      supports_prompt_caching: true
 
   - model_name: claude-3-opus
     litellm_params:
       model: anthropic/claude-3-opus-20240229
       api_key: os.environ/ANTHROPIC_API_KEY
+      drop_params: true
+      supports_prompt_caching: true
 
   - model_name: claude-3-haiku
     litellm_params:
       model: anthropic/claude-3-haiku-20240307
       api_key: os.environ/ANTHROPIC_API_KEY
+      drop_params: true
+      supports_prompt_caching: true
 
 litellm_settings:
   drop_params: true