Add Claude Sonnet 4.6 and 4.5 to GitHub Copilot model catalog (openclaw#20270) thanks @Clawborn

Verified:
- pnpm build
- pnpm check
- pnpm test:macmini

Co-authored-by: Clawborn <261310391+Clawborn@users.noreply.github.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

src/providers/github-copilot-models.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it } from "vitest";
+import { buildCopilotModelDefinition, getDefaultCopilotModelIds } from "./github-copilot-models.js";
+
+describe("github-copilot-models", () => {
+  describe("getDefaultCopilotModelIds", () => {
+    it("includes claude-sonnet-4.6", () => {
+      expect(getDefaultCopilotModelIds()).toContain("claude-sonnet-4.6");
+    });
+
+    it("includes claude-sonnet-4.5", () => {
+      expect(getDefaultCopilotModelIds()).toContain("claude-sonnet-4.5");
+    });
+
+    it("returns a mutable copy", () => {
+      const a = getDefaultCopilotModelIds();
+      const b = getDefaultCopilotModelIds();
+      expect(a).not.toBe(b);
+      expect(a).toEqual(b);
+    });
+  });
+
+  describe("buildCopilotModelDefinition", () => {
+    it("builds a valid definition for claude-sonnet-4.6", () => {
+      const def = buildCopilotModelDefinition("claude-sonnet-4.6");
+      expect(def.id).toBe("claude-sonnet-4.6");
+      expect(def.api).toBe("openai-responses");
+    });
+
+    it("trims whitespace from model id", () => {
+      const def = buildCopilotModelDefinition("  gpt-4o  ");
+      expect(def.id).toBe("gpt-4o");
+    });
+
+    it("throws on empty model id", () => {
+      expect(() => buildCopilotModelDefinition("")).toThrow("Model id required");
+      expect(() => buildCopilotModelDefinition("  ")).toThrow("Model id required");
+    });
+  });
+});