Type Result.files and saveFiles() as arrays

[paulius-petkus]

Task

#94

What is done

• Result.files typed as ResultFile[] (was [ResultFile])
• saveFiles() typed as Promise<string[]> (was Promise<[string]>)

[ResultFile] is a TypeScript tuple with a fixed size of 1, so TypeScript treated every result as having exactly one file. That is wrong for conversions that return several files. Runtime is unchanged; this only affects TypeScript compilation.

TypeScript code	Before	Now
files[1], saved[1], const [a, b] = files	build error	works
files.length === 2	build error	works
files[0], loops, saveFiles(), result.file	works	works
files[0].url with noUncheckedIndexedAccess	works	needs a check, like any array
Code that spells out [ResultFile] / [string]	works	needs updating to arrays

The last two rows are breaking for some TypeScript users, so this should be released as 2.0.0. JavaScript users are not affected.

[Copilot]

Copilot wasn't able to review any files in this pull request. Check if the Files changed in this pull request are included in default exclusions.