Markdown in user messages, with a preview in the composer

User messages are rendered with the same Markdown component as the model's
answers; single line breaks are kept (hard breaks outside code blocks), so
plain multi-line messages look as before. The eye button next to the text
field shows the formatted message before sending. The text sent to the model
is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -3,6 +3,14 @@
 All notable changes to CodeCraft. Versions follow [Semantic Versioning](https://semver.org/);
 until 1.0, minor versions may contain breaking changes.
 
+## [Unreleased]
+
+### Added
+
+- **Markdown in your messages:** your messages are shown formatted like the model's answers
+  (headings, lists, tables, code blocks, quotes, bold/italic); single line breaks stay as typed.
+  The eye button next to the text field shows a preview of the formatted message before sending.
+
 ## [v202611-00016] – 2026-11-10
 
 ### Fixed