Cinematic: Blender billboards for all Sol planets, moons, rings & asteroids

[ThomasAFink]

Summary

Extend --blender-bodies beyond Earth/Moon so the Sol→α Cen matplotlib cinematic composites Blender spin (and ring) assets for every body that has a pack — planets, major moons, ringed giants, and named asteroids — during the Sol zoom-out.

Depends on

• Replace Earth/Moon cinematic dots with Blender body graphics #42 Earth/Moon billboards (PR feat(SOLSYS-42): Blender Earth/Moon billboards in Sol→Centauri cinematic #45)
• Sol planet packs (+ rings) issue
• Major-moon packs issue
• Asteroid / dwarf-planet packs issue

Scope

• Generalize BlenderBodySpriteAtlas / pending-body queue beyond Earth+Moon
• Per-body world radius + LOD: full spin disk when large on screen; fall back to dots when tiny
• Saturn/Uranus/Neptune: composite rings with the planet billboard (or ring overlay) while in frame
• Named asteroids only (Ceres/Vesta/…), not the whole population field
• Keep classic dotted cinematic when --blender-bodies is off
• Performance: don’t load every spin loop if the camera never gets close; lazy-load by zoom stage
• Re-render sol_centauri_cinematic_blender_{light,dark}.gif

Acceptance

• With packs present, Jupiter/Saturn/Mars/… show Blender surfaces in-scene during their zoom stages
• Saturn rings readable during outer-system linger
• Major moons appear when their parent system is framed tightly enough
• Missing packs still degrade to catalog dots/colors
• Runtime stays practical (document expected load; lazy-load OK)
• README notes the expanded --blender-bodies coverage

Out of scope

• Replacing the whole tour with a pure Blender camera path
• Billboarding every asteroid-belt particle

Related

Capstone after the pack issues. Pairs with Sol flyby-beats issue for staging.