feat: add venice provider

[bussyjd]

Relates to:

Issue #1016 - Add Venice AI Provider Integration

Risks

Low - Adds new provider option without modifying existing functionality

• Only affects users who explicitly configure Venice
• No changes to core framework behavior
• No database changes required

Background

What does this PR do?

Adds Venice AI as a new provider option to Eliza framework, offering a privacy-focused, uncensored alternative to existing AI providers.

What kind of change is this?

Features (non-breaking change which adds functionality)

• Adds new Venice provider implementation
• Extends provider types and configurations
• Updates environment variable examples

Documentation changes needed?

My changes require a change to the project documentation.

• Added Venice provider configuration to .env.example
• Adding Venice in the list of supported providers
• Updated provider type definitions
• Added Venice-specific configuration documentation

Testing

Where should a reviewer start?

1. Review the Venice provider implementation in packages/core/src/generation.ts
2. Check environment variable handling in .env.example
3. Review type definitions in packages/core/src/types.ts

Detailed testing steps

1. Copy .env.example to .env
2. Add Venice API credentials
3. Configure character to use Venice provider
4. Test basic text generation functionality
   • Verify privacy headers are properly set
   • Confirm uncensored responses work as expected
   • Check error handling behaves correctly

Discord username

bussyjd#4778