Add HEIC/HEIF image format support #423

[SPLATPLAYS]

#423

[p2r3]

Where did you get this code?

[SPLATPLAYS]

A lot of the decoding code is from the https://github.com/alexcorvi/heic2any docs. Encoding via native HTMLCanvasElement.toBlob is spec'd here https://html.spec.whatwg.org/multipage/canvas.html#dom-canvas-toblob-dev . The rest is glue code.

[SPLATPLAYS]

@p2r3

[p2r3]

I'm a bit suspicious of this pull request being vibecoded, along with possibly some of your others.

• The rate at which you're pumping these out, and how casual your pull requests seem to be, is unusual. It's not impossible by any means, but it also isn't normal for a single contributor to pick up such a wide range of formats, implement each in a single commit, and submit no description or additional notes.
• You've got some weird code comments. Some bother to point out the obvious, others don't. Some have Unicode characters in them (e.g →, ↔, and ≥), which would be annoying to type for a human. The style also seems overall inconsistent, as some are written in perfectly punctuated and capitalized English, while others are in all-lowercase with no punctuation.
• One of the error messages reads Consider converting to PNG or JPEG instead, which is incredibly bizarre for a file converter, especially since the user isn't going to see this error. To me, this reads like an LLM slightly misunderstanding the greater context of the project it's working on.
• You deviate quite a bit from established conventions in the rest of the codebase. Your definition of init defines a return type when our examples and other handlers typically don't. You also just underutilize init in general - you define a canvas during the conversion, whereas other handlers that require a canvas typically do it before.
• It also seems weird to me that you're referring to the HTML spec for canvas.toBlob, when that method has been used countless times throughout this codebase in some of the very earliest image handlers.