Add TreeNav component that groups related entity types into a
collapsible hierarchy for Targets and Sources tabs. Targets tree
shows section-level leaves (Devices, Color Strips, LED Targets,
KC Targets, Pattern Templates) with scroll-to-section on click.
Sources tree groups into Picture, Audio, and Utility categories.
Also fixes missing csAudioTemplates in stream section expand/collapse.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
alexei.dolgolyov
3915573514