Every save creates an immutable revision snapshot. The aside shows a
commit-graph-style timeline (newest first) with vertical line, circle
nodes, version numbers, change type, user, and date. Clicking a past
revision renders it readonly with inline git-diff-style highlights
(changed/added/removed with tinted backgrounds). Compare mode allows
diffing any two arbitrary revisions. MANAGE users can restore old
versions, which creates a new revision preserving full history.
New: HandoverRevisionService, HandoverRevisionRepository,
migration 006, 14 PHPUnit tests, DE/EN translations.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
