Observer position & arena pitch (cross-repo)

[mbreiser]

Summary

Comprehensive observer position feature spanning both MATLAB and web tools.

Scope

Immediate fix:

• PatternPreviewerApp reads wrong field name for arena pitch (rotations instead of rotations_deg in loadArenaConfig())

Full feature:

• Register different observer positions (pitch, translation, height)
• Propagate observer parameters into Pattern Generator UI
• Store observer parameters in V2 pattern headers (interacts with existing observer_id field)
• Update arena config schema to include observer position data

Web side:

• Add observer perspective controls to web tools (arena pitch, observer position)
• See companion issue in webDisplayTools

Design Questions (need discussion)

1. Are observer parameters part of arena config, pattern metadata, or runtime-only?
2. Should observer position be saved with patterns or be a preview-only setting?
3. How does this interact with the existing V2 header observer_id field?

Files to Review

• patternTools/PatternPreviewerApp.m (loadArenaConfig method — immediate bug)
• patternTools/PatternGeneratorApp.m (pitch handling reference)
• configs/arenas/*.yaml (current schema)

Dependency

This work should be completed before the 3D/spherical image dataset integration feature.