fix: make ImageShowTool non-deferred so model can discover and call it

- Change shouldDefer from true to false so ImageShowTool is always
available in the model's tool list without requiring ToolSearch
- Previously the model couldn't find ImageShowTool and fell back to
running standalone.tsx via Bash, whose stdout capture garbled the
Kitty protocol output

Co-Authored-By: Claude Big Pickle <noreply@anthropic.com>

src/tools/ImageShowTool/ImageShowTool.ts

@@ -196,7 +196,7 @@ export const ImageShowTool = buildTool({
   name: IMAGE_SHOW_TOOL_NAME,
   searchHint: 'display an image in the terminal',
   maxResultSizeChars: 10_000,
-  shouldDefer: true,
+  shouldDefer: false,
   async description(input) {
     const { src } = input as { src: string }
     try {