perf(client): render bloom pass at quarter resolution (~16× less fill)

[RZDESIGN]

Summary

The bloom pass (WhiteCoreBloomPass, extending Three.js UnrealBloomPass) is the single most expensive post-processing step. It runs a multi-pass Gaussian blur across a mip chain, and currently operates at full drawing-buffer resolution because EffectComposer.setSize() pushes the same width/height to every pass.

This PR adds one line after the composer resize to override the bloom pass to quarter resolution:

this._bloomPass.setSize(vec2.width >> 2, vec2.height >> 2);

Impact

Display	Before (bloom base)	After (bloom base)	Fill reduction
1080p	1920 × 1080	480 × 270	~16×
1440p	2560 × 1440	640 × 360	~16×
720p	1280 × 720	320 × 180	~16×

The entire mip chain scales down proportionally, so total fragment work across all blur passes drops dramatically.

Why this is safe

Bloom is inherently a soft, blurry glow effect — its purpose is to spread bright highlights across neighboring pixels. At quarter resolution the individual bloom texels are still much smaller than the blur kernel, so the visual result is virtually indistinguishable from full-res bloom. Using >> 2 (bitwise divide by 4) maintains the screen's aspect ratio, avoiding any bloom distortion.

Changes

File	Change
client/src/core/Renderer.ts	Added this._bloomPass.setSize(vec2.width >> 2, vec2.height >> 2) after composer resize

Test Plan

• Compare bloom appearance at 1080p before and after — glow around emissive blocks / entities should look identical
• Check GPU frame time in the debug panel — expect a measurable drop, especially on integrated GPUs
• Resize the browser window and verify bloom still looks correct (resize handler calls _resizePostProcessing)
• Verify on LOW/MEDIUM quality presets where bloom may be disabled — the setSize call is harmless when the pass is inactive