Fix: Copy ProviderOptions when merging provider configurations

[novalis78]

Fixes #1472

Summary

This PR fixes a critical bug where provider-specific options configured via provider_options in crush.json were being silently ignored for all providers.

Problem

The configureProviders function in internal/config/load.go creates provider configurations by copying fields from Catwalk providers and user config, but it was missing the ProviderOptions field. This caused all provider-specific configuration to be lost during the merge process.

Impact

• All providers affected: OpenRouter, OpenAI, custom providers, etc.
• Silent failure: No error or warning shown to users
• Configuration ignored: Features like reasoning parameters, usage tracking options, and custom provider settings were completely ignored

Example Configuration That Didn't Work

{
  "providers": {
    "openrouter": {
      "provider_options": {
        "reasoning": {
          "max_tokens": 2000
        },
        "include_usage": false
      }
    }
  }
}

These options would be loaded from the config file but never applied to requests.

Solution

Added one line at internal/config/load.go:193 to copy the ProviderOptions field:

ProviderOptions:    config.ProviderOptions,

This ensures that provider-specific options from user configuration are properly merged into the final provider config.

Testing

Before fix:

• Provider options present in loaded config
• Options missing after configureProviders
• Requests sent without provider-specific configuration

After fix:

• Provider options preserved through configuration merge
• Options correctly applied to provider requests
• Tested with OpenRouter + Gemini 3 Pro Preview with reasoning parameters

Files Changed

• internal/config/load.go: Added ProviderOptions field copy (1 line)

Scope

This is a minimal, surgical fix that:

• Affects only the configuration merging logic
• Does not change any behavior for users not using provider_options
• Fixes the issue for all current and future providers
• Is backwards compatible