fix: add any_configured() to ProvidersConfig to prevent onboarding 500

[lucaseduoli]

Summary

Onboarding fails with a 500 error when configuring watsonx.ai or ollama providers because ProvidersConfig is missing the any_configured() method that settings.py calls.

Problem

src/api/settings.py line 1088 calls:

current_config.providers.any_configured()

But ProvidersConfig in src/config/config_manager.py only has get_provider_config() — no any_configured() method exists. This raises AttributeError: 'ProvidersConfig' object has no attribute 'any_configured', which surfaces as a 500 error during the onboarding settings save.

Root cause

The any_configured() call was added to settings.py but the corresponding method was never implemented on the ProvidersConfig dataclass.

Fix

Add any_configured() to ProvidersConfig that returns True if any provider's configured flag is set. Each provider dataclass (OpenAIConfig, AnthropicConfig, WatsonXConfig, OllamaConfig) already has a configured: bool field.

Testing

• Configuring watsonx.ai or ollama during onboarding no longer crashes with 500
• any_configured() returns True when at least one provider is configured
• any_configured() returns False when no providers are configured

Closes #1163

[Wallgau]

LGTM