feat(providers): add OpenCode Zen and OpenCode Go providers

nanobot/config/schema.py

@@ -235,6 +235,8 @@ class ProvidersConfig(Base):
     github_copilot: ProviderConfig = Field(default_factory=ProviderConfig, exclude=True)  # Github Copilot (OAuth)
     qianfan: ProviderConfig = Field(default_factory=ProviderConfig)  # Qianfan (百度千帆)
     nvidia: ProviderConfig = Field(default_factory=ProviderConfig)  # NVIDIA NIM (nvapi- keys)
+    opencode_zen: ProviderConfig = Field(default_factory=ProviderConfig)  # OpenCode Zen (curated coding models)
+    opencode_go: ProviderConfig = Field(default_factory=ProviderConfig)  # OpenCode Go (low-cost coding models)
 
     @model_validator(mode="after")
     def convert_extra_providers(self):

nanobot/providers/registry.py

@@ -543,6 +543,26 @@ PROVIDERS: tuple[ProviderSpec, ...] = (
         detect_by_base_keyword="nvidia.com",
         default_api_base="https://integrate.api.nvidia.com/v1",
     ),
+    # OpenCode Zen: curated reliable models for coding agents
+    ProviderSpec(
+        name="opencode_zen",
+        keywords=("opencode_zen", "opencode-zen", "zen"),
+        env_key="OPENCODE_API_KEY",
+        display_name="OpenCode Zen",
+        backend="openai_compat",
+        is_gateway=True,
+        default_api_base="https://opencode.ai/zen/v1",
+    ),
+    # OpenCode Go: low-cost coding models
+    ProviderSpec(
+        name="opencode_go",
+        keywords=("opencode_go", "opencode-go"),
+        env_key="OPENCODE_API_KEY",
+        display_name="OpenCode Go",
+        backend="openai_compat",
+        is_gateway=True,
+        default_api_base="https://opencode.ai/zen/go/v1",
+    ),
     # === Auxiliary (not a primary LLM provider) ============================
     # Groq: mainly used for Whisper voice transcription, also usable for LLM
     ProviderSpec(