fix: propagate drop shadow blur resolution

[avsavani]

Summary

• add resolution support to KawaseBlurFilter
• pass DropShadowFilter's resolution and pixelSize through to its internal Kawase blur pass
• keep blur/drop-shadow padding in sync when kernels or pixel size change at runtime

Why

DropShadowFilter already exposes a resolution option and defaults it to 1, but the internal KawaseBlurFilter was constructed without that value. On HiDPI/Retina renderers the blur pass can therefore do unnecessary DPR-scaled work, which is especially expensive for high-quality shadows.

This keeps the fix small and centralized: KawaseBlurFilter now owns its resolution option and pixel-size-aware padding, while DropShadowFilter reuses the inner blur's actual padding instead of duplicating an approximate formula.

Validation

• npm run types
• npm run lint
• npm run build

Fixes #327