feat(ai): Add zAI provider support

- Add 'zai' as a KnownProvider type
- Add ZAI_API_KEY environment variable mapping
- Generate 4 zAI models (glm-4.5-air, glm-4.5v, etc.) using anthropic-messages API
- Add comprehensive test coverage for zAI provider in generate.test.ts and empty.test.ts
- Models support reasoning/thinking capabilities and tool calling

packages/ai/test/empty.test.ts

@@ -262,4 +262,24 @@ describe("AI Providers Empty Message Tests", () => {
 			await testEmptyAssistantMessage(llm);
 		});
 	});
+
+	describe.skipIf(!process.env.ZAI_API_KEY)("zAI Provider Empty Messages", () => {
+		const llm = getModel("zai", "glm-4.5-air");
+
+		it("should handle empty content array", async () => {
+			await testEmptyMessage(llm);
+		});
+
+		it("should handle empty string content", async () => {
+			await testEmptyStringMessage(llm);
+		});
+
+		it("should handle whitespace-only content", async () => {
+			await testWhitespaceOnlyMessage(llm);
+		});
+
+		it("should handle empty assistant message in conversation", async () => {
+			await testEmptyAssistantMessage(llm);
+		});
+	});
 });