Git identity from the settings for all agent shells, terminals and the git panel

Set GIT_AUTHOR_*/GIT_COMMITTER_* from Settings → Account → Git (also inside the
sandbox), so a repository's own user.name/user.email no longer wins; tell agents
not to change the git identity.

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

CHANGELOG.md

@@ -3,6 +3,15 @@
 All notable changes to CodeCraft. Versions follow [Semantic Versioning](https://semver.org/);
 until 1.0, minor versions may contain breaking changes.
 
+## [Unreleased]
+
+### Fixed
+
+- Commits by agents, terminals and the git panel always use the name and e-mail from
+  *Settings → Account → Git* – also in repositories that have their own `user.name`/`user.email`
+  (agents had set those as a workaround while no identity was configured). Agents are told not
+  to change the git identity.
+
 ## [v202611-00004] – 2026-11-09
 
 ### Added