feat(registry): add client model support check for executor filtering

- Introduced `ClientSupportsModel` function to `ModelRegistry` for verifying client support for specific models.
- Integrated model support validation into executor candidate filtering logic.
- Updated CLIProxy registry interface to include the new support check method.

sdk/cliproxy/auth/manager.go

@@ -841,6 +841,8 @@ func (m *Manager) pickNext(ctx context.Context, provider, model string, opts cli
 		return nil, nil, &Error{Code: "executor_not_found", Message: "executor not registered"}
 	}
 	candidates := make([]*Auth, 0, len(m.auths))
+	modelKey := strings.TrimSpace(model)
+	registryRef := registry.GetGlobalRegistry()
 	for _, candidate := range m.auths {
 		if candidate.Provider != provider || candidate.Disabled {
 			continue
@@ -848,6 +850,9 @@ func (m *Manager) pickNext(ctx context.Context, provider, model string, opts cli
 		if _, used := tried[candidate.ID]; used {
 			continue
 		}
+		if modelKey != "" && registryRef != nil && !registryRef.ClientSupportsModel(candidate.ID, modelKey) {
+			continue
+		}
 		candidates = append(candidates, candidate)
 	}
 	if len(candidates) == 0 {