Implement automatic save functionality for Potree viewer modifications

[mosoriob]

Feature Request

Implement automatic saving of user modifications in the Potree viewer back to CKAN resources to enable persistent collaborative analysis.

Current Documentation References

From src/ckanext-potree/README-pipeline.md:

Line 435:

Analysis Persistence: All work automatically saved and versioned in CKAN

Lines 363-364:

Persistent Annotations: User annotations and measurements saved to CKAN resource
Collaborative Editing: Multiple users can contribute to scene configurations

Line 370:

Save to CKAN: User modifications automatically sync back to CKAN resource

Required Functionality

Core Auto-Save Features

• Real-time Sync: Automatic saving of scene modifications to CKAN resources
• Bidirectional Data Flow: Changes in viewer sync back to CKAN API
• Persistent Storage: Annotations, measurements, and view configurations saved automatically

Specific Data to Auto-Save

• User annotations and 3D markers
• Measurement calculations (distance, area, volume)
• Camera positions and view configurations
• Visualization settings and filters
• Analysis notes and documentation

Technical Implementation

• Integration with CKAN API for resource updates
• Conflict resolution for simultaneous edits
• Permission validation before saves
• Background sync without interrupting user workflow

Benefits

• Enhanced collaborative workflows
• Persistent analysis sessions
• Reduced risk of data loss
• Seamless integration with CKAN's resource management
• Professional-grade research documentation

Acceptance Criteria

• User modifications automatically save to CKAN resources
• No manual save action required from users
• Real-time sync with proper conflict resolution
• Permission-based write access validation
• Background saving without UI interruption
• Integration with CKAN's versioning system

Priority

High - Core feature for collaborative analysis workflow

Labels

• enhancement
• auto-save
• collaboration
• ckan-integration