feat(angular-3d): add metaball component with ray marching shader

- Ray marching SDF implementation with smooth blob blending (smin)
- 6 color presets: moody, cosmic, neon, sunset, holographic, minimal
- Interactive cursor tracking with smooth interpolation
- Adaptive quality: 48 ray march steps (desktop), 16 (mobile)
- Full lighting model with AO, soft shadows, fresnel
- Proper cleanup via DestroyRef

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Abdallah-khalil

libs/angular-3d/src/lib/primitives/index.ts

@@ -41,3 +41,6 @@ export * from './environment.component';
 
 // Cloud components
 export * from './cloud-layer.component';
+
+// Metaball ray-marching component
+export * from './metaball.component';