Add support for Chrome HDR mode for WebGPU

[mvaligursky]

Fixes #6975

This adds support for HDR displays for WebGPU (new in Chrome 129).

There is a new public constant that can be used to request HDR mode:
DISPLAYFORMAT_HDR // this is now public

also, new API to test if HDR is active:
GraphicsDevice.isHdr

Notes:

• few examples were updated to test this.
• old bloom was removed from the example as that is LDR implementation
• WebGPU implements single non-specific tonemapping, so it does not exactly match our tonemapping options. They plan to expose additional options in the future.
• there is an issue with some more advanced examples, I'll investigate more and likely open chromium issue, as the browser rendering gets broken in those cases.

[slimbuck]

The naming is becoming a little confusing since we can already render to HDR backbuffer.

[mvaligursky]

The naming is becoming a little confusing since we can already render to HDR backbuffer.

How can we already render to HDR backbuffer?

[slimbuck]

SHADER_FORWARDHDR

[mvaligursky]

ahh that .. that was removed in v2 .. confusion solved ;)
But that would not do rendering to HDR backbuffer, only HDR render target.

[slimbuck]

HDR backbuffer, only HDR render target.

yeah this bit, confusing

[slimbuck]

Only mentioning so we can perhaps make the difference explicit in docs. Though it may not be necessary since as you say, it's gone from v2.0.

[willeastcott]

Link displayFormat?

[mvaligursky]

we cannot link to options.displayFormat directly I think, but I link a function accepting this options object.

[MAG-AdrianMeredith]

kewl, this looks so much nicer than my hack from a while back