feat(effects): add bloom effect

[ibgreen]

Summary

• add bloom post-processing shader pass with configurable radius, threshold, and intensity
• refine bloom shader to blur bright areas with weighted kernel for a softer glow
• document bloom usage

Testing

• corepack yarn lint modules/effects/src/passes/postprocessing/image-blur-filters/bloom.ts docs/api-reference/shadertools/shader-passes/image-processing.mdx (fails: Unable to resolve path to module '@luma.gl/shadertools' and others)
• npx eslint modules/effects/src/passes/postprocessing/image-blur-filters/bloom.ts docs/api-reference/shadertools/shader-passes/image-processing.mdx (fails: Parsing error: Unexpected character '#')
• corepack yarn test node modules/effects/test/passes/image-blur-filters/bloom.spec.ts (passes 0 tests: No tests here; Use browser tests)

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https://chatgpt.com/codex/tasks/task_e_688e6bde939083289bad675b0b095a9e