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.ts

@@ -7,6 +7,8 @@ const DEFAULT_MAX_TOKENS = 8192;
 // We keep this list intentionally broad; if a model isn't available Copilot will
 // return an error and users can remove it from their config.
 const DEFAULT_MODEL_IDS = [
+  "claude-sonnet-4.6",
+  "claude-sonnet-4.5",
   "gpt-4o",
   "gpt-4.1",
   "gpt-4.1-mini",