chore: remove iFlow-related modules and dependencies

- Deleted `iflow` provider implementation, including thinking configuration (`apply.go`) and authentication modules.
- Removed iFlow-specific tests, executors, and helpers across SDK and internal components.
- Updated all references to exclude iFlow functionality.

sdk/cliproxy/auth/conductor_overrides_test.go

@@ -69,7 +69,7 @@ func TestManager_ShouldRetryAfterError_UsesOAuthModelAliasForCooldown(t *testing
 	m := NewManager(nil, nil, nil)
 	m.SetRetryConfig(3, 30*time.Second, 0)
 	m.SetOAuthModelAlias(map[string][]internalconfig.OAuthModelAlias{
-		"iflow": {
+		"kimi": {
 			{Name: "deepseek-v3.1", Alias: "pool-model"},
 		},
 	})
@@ -80,7 +80,7 @@ func TestManager_ShouldRetryAfterError_UsesOAuthModelAliasForCooldown(t *testing
 
 	auth := &Auth{
 		ID:       "auth-1",
-		Provider: "iflow",
+		Provider: "kimi",
 		ModelStates: map[string]*ModelState{
 			upstreamModel: {
 				Unavailable:    true,
@@ -99,7 +99,7 @@ func TestManager_ShouldRetryAfterError_UsesOAuthModelAliasForCooldown(t *testing
 	}
 
 	_, _, maxWait := m.retrySettings()
-	wait, shouldRetry := m.shouldRetryAfterError(&Error{HTTPStatus: 429, Message: "quota"}, 0, []string{"iflow"}, routeModel, maxWait)
+	wait, shouldRetry := m.shouldRetryAfterError(&Error{HTTPStatus: 429, Message: "quota"}, 0, []string{"kimi"}, routeModel, maxWait)
 	if !shouldRetry {
 		t.Fatalf("expected shouldRetry=true, got false (wait=%v)", wait)
 	}