Create task task-033

backlog/tasks/task-033 - Version-History-&-Reversion-System-with-Visual-Diffs.md

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+---
+id: task-033
+title: Version History & Reversion System with Visual Diffs
+status: In Progress
+assignee: []
+created_date: '2025-12-04 21:44'
+labels:
+  - feature
+  - version-control
+  - automerge
+  - r2
+  - ui
+dependencies: []
+priority: high
+---
+
+## Description
+
+<!-- SECTION:DESCRIPTION:BEGIN -->
+Implement a comprehensive version history and reversion system that allows users to:
+1. View and revert to historical board states
+2. See visual diffs highlighting new/deleted shapes since their last visit
+3. Walk through CRDT history step-by-step
+4. Restore accidentally deleted shapes
+
+Key features:
+- Time rewind button next to the star dashboard button
+- Popup menu showing historical versions
+- Yellow glow on newly added shapes (first time user sees them)
+- Dim grey on deleted shapes with "undo discard" option
+- Permission-based (admin, editor, viewer)
+- Integration with R2 backups and Automerge CRDT history
+- Compare user's local state with server state to highlight diffs
+<!-- SECTION:DESCRIPTION:END -->
+
+## Acceptance Criteria
+<!-- AC:BEGIN -->
+- [ ] #1 Version history button renders next to star button with time-rewind icon
+- [ ] #2 Clicking button opens popup showing list of historical versions
+- [ ] #3 User can select a version to preview or revert to
+- [ ] #4 Newly added shapes since last user visit have yellow glow effect
+- [ ] #5 Deleted shapes show dimmed with 'undo discard' option
+- [ ] #6 Version navigation respects user permissions (admin/editor/viewer)
+- [ ] #7 Works with R2 backup snapshots for coarse-grained history
+- [ ] #8 Leverages Automerge CRDT for fine-grained change tracking
+- [ ] #9 User's last-seen state stored in localStorage for diff comparison
+- [ ] #10 Visual effects are subtle and non-intrusive
+<!-- AC:END -->