apiKeyEnvNames function
The env names that can hold provider's API key: the catalog spec's
names (providerCatalog; copilot → COPILOT_GITHUB_TOKEN,
kimi → KIMI_API_KEY, …), plus the two non-catalog slots; unknown kinds
keep the historical OpenRouter/OpenAI pair.
Implementation
List<String> apiKeyEnvNames(String provider) => switch (provider) {
'vision' => const ['VISION_API_KEY'],
'transcribe' => const ['TRANSCRIBE_API_KEY'],
_ =>
providerCatalog[provider]?.apiKeyEnvNames ??
const ['OPENROUTER_API_KEY', 'OPENAI_API_KEY'],
};