Sticker generation was failing when using newer GPT image models
(gpt-image-1, gpt-image-1-mini, gpt-image-1.5). The issue occurred
because stickers requested 256x256 size, but these models only support
1024x1024, 1536x1024, 1024x1536, and auto.
To reproduce, send `!bai sticker Something` to an agent configured
with a GPT image model. The error was:
invalid_request_error: Invalid value: '256x256'. Supported values
are: '1024x1024', '1024x1536', '1536x1024', and 'auto'. (param: size)
(code: invalid_value)
The fix replaces the hardcoded 256x256 size override with a
`smallest_size_possible` flag, letting each provider determine the
appropriate sticker size based on the model being used.
The `openai_compat` provider still defaults to requesting 256x256 in all cases
(regardless of model name).
This is a huge patch which does some major refactoring like:
- renaming "Image Generation" to "Image Creation" in most places,
to better match its new command (`!bai image create`)
- relocating image creation command (`!bai image` -> `!bai image create`),
so it wouldn't conflict with the new image editing command (`!bai image edit`)
- introducing a new image editing command (`!bai image edit`), which
is meant to work only with the OpenAI provider, but doesn't fully work yet
due to https://github.com/64bit/async-openai/issues/364, though a next patch will fix it
- adding support for reading images off of Matrix conversations and forwarding them to
text conversations. Works for OpenAI, but not for Anthropic yet
(requires custom patches) and not for OpenAI-Compat (no support for
images there)
- relocating some utils around (base64, mime)
