feat(renderer): add HDR target, Bloom resources, and ACES tonemap

- Add hdr.rs with HdrTarget (Rgba16Float render target) and HDR_FORMAT constant
- Add bloom.rs with BloomResources (5-level mip chain), BloomUniform, and mip_sizes()
- Add tonemap.rs with TonemapUniform and CPU-side aces_tonemap() for testing
- Export all new types from lib.rs
- 33 tests passing (26 existing + 3 bloom + 4 tonemap)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

crates/voltex_renderer/src/lib.rs

@@ -19,6 +19,9 @@ pub mod deferred_pipeline;
 pub mod ssgi;
 pub mod rt_accel;
 pub mod rt_shadow;
+pub mod hdr;
+pub mod bloom;
+pub mod tonemap;
 
 pub use gpu::{GpuContext, DEPTH_FORMAT};
 pub use light::{CameraUniform, LightUniform, LightData, LightsUniform, MAX_LIGHTS, LIGHT_DIRECTIONAL, LIGHT_POINT, LIGHT_SPOT};
@@ -43,3 +46,6 @@ pub use deferred_pipeline::{
 pub use ssgi::{SsgiResources, SsgiUniform, SSGI_OUTPUT_FORMAT};
 pub use rt_accel::{RtAccel, RtInstance, BlasMeshData, mat4_to_tlas_transform};
 pub use rt_shadow::{RtShadowResources, RtShadowUniform, RT_SHADOW_FORMAT};
+pub use hdr::{HdrTarget, HDR_FORMAT};
+pub use bloom::{BloomResources, BloomUniform, mip_sizes, BLOOM_MIP_COUNT};
+pub use tonemap::{TonemapUniform, aces_tonemap};