fix(coding-agent): preserve indentation in ANSI-rendered HTML export

HTML div elements collapse whitespace by default, stripping leading
spaces from ANSI-rendered tool output (e.g. JSON code blocks).
Added white-space: pre-wrap to .ansi-line class.

packages/coding-agent/CHANGELOG.md

@@ -7,6 +7,10 @@
 - API keys in `auth.json` now support shell command resolution (`!command`) and environment variable lookup, matching the behavior in `models.json`
 - Added `minimal-mode.ts` example extension demonstrating how to override built-in tool rendering for a minimal display mode
 
+### Fixed
+
+- Fixed HTML export losing indentation in ANSI-rendered tool output (e.g. JSON code blocks in custom tool results)
+
 ## [0.51.6] - 2026-02-04
 
 ### New Features

packages/coding-agent/src/core/export-html/template.css

@@ -503,6 +503,10 @@
       display: block;
     }
 
+    .ansi-line {
+      white-space: pre-wrap;
+    }
+
     .tool-images {
     }