Z.AI Integration

[kevariable]

Description

Add Z AI provider integration with Text and Structure support

This PR adds a new AI provider "Z" to Prism, enabling users to interact with Z AI models for text generation and structured data responses.

Features Added:

• Text Generation: Full support for text generation with prompts, system prompts, and temperature/top_p configuration
• Structured Output: Support for structured data generation with JSON schema validation
• Tool Calling: Multi-step tool execution with parallel tool calls support
• Error Handling: Proper exception handling including rate limiting (429 errors)
• Flexible Configuration: Support for custom client options and retry configuration

Provider Implementation:

• Provider class: Prism\Prism\Providers\Z\ZProvider
• Text handler: Prism\Prism\Providers\Z\Handlers\Text
• Structure handler: Prism\Prism\Providers\Z\Handlers\Structure
• Comprehensive test coverage for all features

Usage Example:

// Text generation
$response = Prism::text()
    ->using(Provider::Z, 'z-model')
    ->withPrompt('Hello, world!')
    ->asText();

// Structured output
$response = Prism::structured()
    ->using(Provider::Z, 'z-model')
    ->with(schema: ['name' => 'string'], prompt: 'Extract a name')
    ->asStructured();

[kevariable]

This is my first time contribute to Open Source, very happy to contribute this!

Haven't test yet about Stream, but looking forward to update in meaning time.

Tested with Structured with Tools, Text, Text with Tools, Tools built-in