test: add Phase 12 Record Detail & Navigation L2/L3 feature tests

Add comprehensive tests for 7 components:
- InlineCreateRelated: tabs, form submission, search, linking
- RichTextCommentInput: toolbar, bold, mentions, preview, submit
- DiffView: old/new values, green/red styling, number diffs, mode toggle
- RecordNavigationEnhanced: nav buttons, position, disabled states, search
- RelationshipGraph: SVG, central/related nodes, click handler
- CommentAttachment: list, thumbnails, file icons, file sizes
- PointInTimeRestore: timeline, revision details, restore confirmation

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Copilot