feat: Add OpenCode Zen as a provider

OpenCode Zen (opencode.ai) is a curated AI gateway with tested/verified
models for coding agents. It offers:

- Free models: Big Pickle, MiniMax M2.5 Free, Kimi K2.5 Free
- Premium models: Claude, GPT-5.x, Gemini 3, Qwen3 Coder, etc.
- Pay-as-you-go pricing, often cheaper than direct providers

Provider details:
- ID: opencode
- Base URL: https://opencode.ai/zen/v1
- Auth: API key from opencode.ai/auth
- Format: OpenAI-compatible chat/completions

Includes:
- Provider definition with 40+ models
- CLI argument --opencode-api-key / OPENCODE_API_KEY env var
- Credential file mapping (opencode.key)
- Help text pointing to opencode.ai/auth

Author: rexlunae

src/main.rs

@@ -198,6 +198,9 @@ struct OnboardArgs {
     /// OpenRouter API key
     #[arg(long, value_name = "KEY", env = "OPENROUTER_API_KEY")]
     openrouter_api_key: Option<String>,
+    /// OpenCode Zen API key
+    #[arg(long, value_name = "KEY", env = "OPENCODE_API_KEY")]
+    opencode_api_key: Option<String>,
     /// Gemini API key
     #[arg(long, value_name = "KEY", env = "GEMINI_API_KEY")]
     gemini_api_key: Option<String>,
@@ -1449,6 +1452,7 @@ fn run_import(args: &ImportArgs, config: &mut Config) -> Result<()> {
             ("anthropic.key", "Anthropic"),
             ("openai.key", "OpenAI"),
             ("openrouter.key", "OpenRouter"),
+            ("opencode.key", "OpenCode Zen"),
             ("gemini.key", "Gemini"),
             ("xai.key", "xAI"),
         ];
@@ -1598,6 +1602,7 @@ fn run_import(args: &ImportArgs, config: &mut Config) -> Result<()> {
                     ("anthropic.key", "ANTHROPIC_API_KEY"),
                     ("openai.key", "OPENAI_API_KEY"),
                     ("openrouter.key", "OPENROUTER_API_KEY"),
+                    ("opencode.key", "OPENCODE_API_KEY"),
                     ("gemini.key", "GEMINI_API_KEY"),
                     ("xai.key", "XAI_API_KEY"),
                 ];

src/providers.rs

@@ -195,6 +195,54 @@ pub const PROVIDERS: &[ProviderDef] = &[
         help_url: None,
         help_text: Some("No key needed — exo cluster. Default port 52415. Install: github.com/exo-explore/exo"),
     },
+    ProviderDef {
+        id: "opencode",
+        display: "OpenCode Zen",
+        auth_method: AuthMethod::ApiKey,
+        secret_key: Some("OPENCODE_API_KEY"),
+        device_flow: None,
+        // OpenAI-compatible chat/completions endpoint for most models.
+        // Claude models also work here via OpenCode's OpenAI-compatible layer.
+        base_url: Some("https://opencode.ai/zen/v1"),
+        models: &[
+            // Free models
+            "big-pickle",
+            "minimax-m2.5-free",
+            "kimi-k2.5-free",
+            // Claude models (via OpenAI-compatible API)
+            "claude-opus-4-6",
+            "claude-opus-4-5",
+            "claude-sonnet-4-5",
+            "claude-sonnet-4",
+            "claude-haiku-4-5",
+            "claude-3-5-haiku",
+            // GPT models
+            "gpt-5.2",
+            "gpt-5.2-codex",
+            "gpt-5.1",
+            "gpt-5.1-codex",
+            "gpt-5.1-codex-max",
+            "gpt-5.1-codex-mini",
+            "gpt-5",
+            "gpt-5-codex",
+            "gpt-5-nano",
+            // Gemini models
+            "gemini-3-pro",
+            "gemini-3-flash",
+            // Other models
+            "minimax-m2.5",
+            "minimax-m2.1",
+            "glm-5",
+            "glm-4.7",
+            "glm-4.6",
+            "kimi-k2.5",
+            "kimi-k2-thinking",
+            "kimi-k2",
+            "qwen3-coder",
+        ],
+        help_url: Some("https://opencode.ai/auth"),
+        help_text: Some("Get a key at opencode.ai/auth — includes free models (Big Pickle, MiniMax, Kimi)"),
+    },
     ProviderDef {
         id: "custom",
         display: "Custom / OpenAI-compatible endpoint",

tests/golden/help_gateway.txt

@@ -7,6 +7,7 @@ Commands:
   stop     Stop a running gateway
   restart  Restart the gateway
   status   Show gateway status
+  reload   Reload gateway configuration without restarting
   run      Run the gateway in the foreground (like `rustyclaw-gateway`)
   help     Print this message or the help of the given subcommand(s)