fix: resolve config dict api_key not being unpacked in OpenAI-based providers

[lfnovo]

Summary

• Fixes Bug: OpenRouter provider ignores api_key from config dict #68: OpenRouter (and other OpenAI-based providers) were ignoring api_key passed via the config dict
• Fixed providers: LLM openrouter, deepseek, xai and STT groq
• Added regression tests for config dict initialization

Root Cause

Providers that inherit from OpenAI-compatible parent classes were checking for api_key before the config dict was unpacked by the base class's __post_init__. Additionally, when calling super().__post_init__() first, the parent OpenAI class would set its own defaults before the child provider could set its own.

Fix

For providers that inherit from OpenAI-compatible parent classes, manually extract api_key and base_url from the config dict before setting provider-specific defaults:

def __post_init__(self):
    # Extract api_key and base_url from config dict first
    if hasattr(self, "config") and self.config:
        if "api_key" in self.config:
            self.api_key = self.config["api_key"]
        if "base_url" in self.config:
            self.base_url = self.config["base_url"]

    # Set provider-specific defaults
    self.api_key = self.api_key or os.getenv("PROVIDER_API_KEY")
    # ...
    
    super().__post_init__()

Test plan

• All existing tests pass (390 LLM provider tests)
• Added tests for config dict initialization:
  • test_initialization_with_api_key_in_config
  • test_initialization_with_base_url_in_config
  • test_initialization_with_api_key_and_base_url_in_config

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.

[cubic-dev-ai]

No issues found across 8 files