feat: complete Groq provider integration and add Kimi K2 model (#978)

* feat: complete Groq provider integration and add Kimi K2 model

- Add missing getRequiredApiKeyName() method to GroqProvider class
- Register GroqProvider in ai-services-unified.js PROVIDERS object
- Add Groq API key handling to config-manager.js (isApiKeySet and getMcpApiKeyStatus)
- Add GROQ_API_KEY to env.example with format hint
- Add moonshotai/kimi-k2-instruct model to Groq provider ($1/$3 per 1M tokens, 16k max)
- Fix import sorting for linting compliance
- Add GroqProvider mock to ai-services-unified tests

Fixes missing implementation pieces that prevented Groq provider from working.

* chore: improve changeset

---------

Co-authored-by: Ben Vargas <ben@example.com>
Co-authored-by: Ralph Khreish <35776126+Crunchyman-ralph@users.noreply.github.com>

src/ai-providers/groq.js

@@ -14,6 +14,14 @@ export class GroqProvider extends BaseAIProvider {
 		this.name = 'Groq';
 	}
 
+	/**
+	 * Returns the environment variable name required for this provider's API key.
+	 * @returns {string} The environment variable name for the Groq API key
+	 */
+	getRequiredApiKeyName() {
+		return 'GROQ_API_KEY';
+	}
+
 	/**
 	 * Creates and returns a Groq client instance.
 	 * @param {object} params - Parameters for client initialization