fix: align OpenCode Zen billing copy (#9998) (thanks @therealZpoint-bot)

OpenCode Zen is a pay-as-you-go token-based API, not a $200/month
subscription. The subscription tiers ($20/$100/$200) are OpenCode Black,
a separate product.

This fixes the misleading comment that conflated Zen with Black.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/agents/opencode-zen-models.ts

@@ -1,8 +1,11 @@
 /**
  * OpenCode Zen model catalog with dynamic fetching, caching, and static fallback.
  *
- * OpenCode Zen is a $200/month subscription that provides proxy access to multiple
- * AI models (Claude, GPT, Gemini, etc.) through a single API endpoint.
+ * OpenCode Zen is a pay-as-you-go token-based API that provides access to curated
+ * models optimized for coding agents. It uses per-request billing with auto top-up.
+ *
+ * Note: OpenCode Black ($20/$100/$200/month subscriptions) is a separate product
+ * with flat-rate usage tiers. This module handles Zen, not Black.
  *
  * API endpoint: https://opencode.ai/zen/v1
  * Auth URL: https://opencode.ai/auth

src/commands/auth-choice.apply.api-providers.ts

@@ -752,7 +752,7 @@ export async function applyAuthChoiceApiProviders(
         [
           "OpenCode Zen provides access to Claude, GPT, Gemini, and more models.",
           "Get your API key at: https://opencode.ai/auth",
-          "Requires an active OpenCode Zen subscription.",
+          "OpenCode Zen bills per request. Check your OpenCode dashboard for details.",
         ].join("\n"),
         "OpenCode Zen",
       );