fix(im): fall back to workspace-file delivery when non-vision models reject images

CHANGELOG.md

@@ -6,6 +6,11 @@ This file records the notable changes in each dsh-im release. Its format follows
 
 ## [Unreleased]
 
+### Added / 新增
+
+- 非视觉模型收到图片时不再直接报错丢图：宿主以 `MODEL_DOES_NOT_SUPPORT_IMAGES` 拒绝带图片的 prompt 后，自动把同一批图片字节按入站文件管线落盘到 Session 工作区，并以"原文本 + 工具分析指引 + `<dsh_im_files>` 清单"的纯文本 prompt 复用同一 rpcId 重试一次，使非视觉模型仍可通过 run_code/pwsh 等工具识图；视觉模型与文件消息行为不变，其余图片错误仍按原样提示。
+  Sending an image to a non-vision model no longer fails outright: when the Host rejects an image-bearing prompt with `MODEL_DOES_NOT_SUPPORT_IMAGES`, the same image bytes are automatically staged into the Session workspace through the inbound-file pipeline and retried once as a text-only prompt (original text plus tool-analysis guidance and the `<dsh_im_files>` manifest) under the same rpcId, so non-vision models can still inspect images via tools such as run_code/pwsh. Vision models and file messages are unchanged, and other image errors keep their existing messages.
+
 ## [4.4.0] - 2026-09-01
 
 ### Added / 新增