feat: Add Zhipu (智谱) image generation provider

tests/tools/test_image_generation_tool.py

@@ -171,6 +171,39 @@ async def test_generate_image_tool_allows_ollama_without_api_key(
     assert fake.calls[0]["image_size"] == "1K"
 
 
+@pytest.mark.asyncio
+async def test_generate_image_tool_allows_zhipu_without_api_key(
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    set_config_path(tmp_path / "config.json")
+    FakeImageClient.instances = []
+    monkeypatch.setattr(
+        "nanobot.agent.tools.image_generation.get_image_gen_provider",
+        lambda name: FakeImageClient if name == "zhipu" else None,
+    )
+    tool = ImageGenerationTool(
+        workspace=tmp_path,
+        config=ImageGenerationToolConfig(
+            enabled=True,
+            provider="zhipu",
+            model="glm-image",
+        ),
+        provider_configs={"zhipu": ProviderConfig(api_base="https://open.bigmodel.cn/api/paas/v4")},
+    )
+
+    result = await tool.execute(prompt="draw a cat")
+
+    payload = json.loads(result)
+    assert len(payload["artifacts"]) == 1
+
+    fake = FakeImageClient.instances[0]
+    assert fake.kwargs["api_key"] is None
+    assert fake.kwargs["api_base"] == "https://open.bigmodel.cn/api/paas/v4"
+    assert fake.calls[0]["aspect_ratio"] == "1:1"
+    assert fake.calls[0]["image_size"] == "1K"
+
+
 @pytest.mark.asyncio
 async def test_generate_image_tool_rejects_reference_outside_workspace(tmp_path: Path) -> None:
     set_config_path(tmp_path / "config.json")