[EVAL] API key from Env Var support

[daniel-lxs]

🧪 Evaluation PR for Testing

This is an automated test PR created for evaluation purposes.

---

Related GitHub Issue

Closes: #4337

Description

This PR adds support for obtaining API keys from the environment. A checkbox is added to each configuration that allows inputting an API key -- when checked, a given environment variable (eg, OPENAI_API_KEY, etc) is consulted for the key and the user is not required to provide one in the configuration. Env Var key is predictable but not editable.

Test Procedure

I tested this using VS Code run configurations, where the expected environment variable could be provided or omitted.

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes (if applicable).
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).

A documentation update is advised, to describe environment variable usage to supply API keys.

• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Summary

Adds support for using environment variables for API keys across multiple providers, updates UI components to reflect this, and enhances testing and translation capabilities.

• Behavior:
  • Adds support for API keys from environment variables for providers like anthropic, glama, openrouter, openai, gemini, mistral, deepseek, unbound, requesty, xai, groq, chutes, litellm.
  • Updates validateModelsAndKeysProvided() to check for environment variable usage for API keys.
• UI Components:
  • Introduces ApiKey component to handle API key input and environment variable toggle.
  • Updates various provider components to use the new ApiKey component.
• Testing:
  • Adds comprehensive tests for environment variable integration and the ApiKey component.

[roo-code-dan]

Reviewing API key environment variable implementation

[roo-code-dan]

Typo in constant name: MOONSHOOT should be MOONSHOT.

Suggested change

	MOONSHOOT: 'MOONSHOT_API_KEY',
	MOONSHOT: 'MOONSHOT_API_KEY',

[roo-code-dan]

This references the typo MOONSHOOT constant. After fixing the constant name to MOONSHOT, this should be updated to API_KEYS.MOONSHOT.

Suggested change

	options.moonshotApiKey = getEnvVar(API_KEYS.MOONSHOOT, options.moonshotApiKey)
	options.moonshotApiKey = getEnvVar(API_KEYS.MOONSHOT, options.moonshotApiKey)

[roo-code-dan]

Multiple providers are missing validation updates for environment variable support. The PR adds configUseEnvVars support to providers like cerebras, fireworks, featherless, io-intelligence, vercel-ai-gateway, huggingface, deepinfra, doubao, moonshot, sambanova, and zai in buildApiHandler(), but their validation logic in this file was not updated to accept environment variables as an alternative to direct API keys. This means users will get validation errors even when they have valid environment variables configured.