docs(sdk): explain capability resolution and image delivery contracts - #958

Running Vale across on the following files affected by this PR:

- sdk/guides/llm-image-input.mdx

Attempting to initialize Vale linter...
No customer vale configuration detected. Using Mintlify's default configuration.
Attempting to run Vale spellcheck...
Vale spellcheck completed successfully.

sdk/guides/llm-image-input.mdx:
	- 3:29    Did you really mean 'multimodal'?


Found 1 suggested changes across 1 files in 452.15ms