补齐图标 spritesheet 请求的 provider_model

editor_project_icon 的 EditorImageProviderRequest 增加 provider_model 字段

参考图存在时按编辑模型 gpt-image-2.5-sunburst-c 提交，nanobanana 与无参考图分支分别沿用自身模型

server-rs/crates/api-server/src/editor_project_icon.rs

@@ -57,7 +57,10 @@ use crate::{
         normalize_generated_image_asset_mime,
     },
     http_error::AppError,
-    openai_image_generation::{build_openai_image_http_client, require_openai_image_settings},
+    openai_image_generation::{
+        GPT_IMAGE_2_5_EDIT_MODEL, GPT_IMAGE_2_5_GENERATION_MODEL, build_openai_image_http_client,
+        require_openai_image_settings,
+    },
     platform_errors::{is_retryable_llm_error, map_llm_error, map_oss_error},
     prompt::icon_spec::{PROMPT_MAX_LEN, build_extra_param_prompt, get_gen_icon_spec_prompt},
     request_context::RequestContext,
@@ -1719,6 +1722,15 @@ pub(crate) async fn generate_editor_icon_spritesheet_for_owner(
                     &settings,
                     EditorImageProviderRequest {
                         model: generation_options.model,
+                        provider_model: if generation_options.model
+                            == EDITOR_IMAGE_MODEL_NANOBANANA2
+                        {
+                            generation_options.model
+                        } else if reference_images.is_empty() {
+                            GPT_IMAGE_2_5_GENERATION_MODEL
+                        } else {
+                            GPT_IMAGE_2_5_EDIT_MODEL
+                        },
                         prompt: prompt.as_str(),
                         negative_prompt: None,
                         size,