Re-export FSRS constants

@dae, the constant has been exposed in fsrs-rs. But the affected code is in TypeScript.

https://github.com/open-spaced-repetition/fsrs-rs/blob/75cfeeaaf560bf9f30a714b42dccb3fd2a901696/src/lib.rs#L21

_Originally posted by @L-M-Sherlock in https://github.com/ankitects/anki/issues/4096#issuecomment-2986810890_

One way we could solve this is by adding a Rust binary that exports the constants to a ts file. But that adds an extra build step, with a bit of a performance impact. Another option would be to define a new protobuf struct that holds FSRS constants, and pass that into our pages that need the constants (e.g. returning it as part of the card info).

Start with fsrs-rs/src/lib.rs around line 21, then locate the affected TypeScript code and the pages that need FSRS constants. Compare the proposed Rust-generated TypeScript file with passing a protobuf struct through card info; the work is done when the constants are available to those pages through a chosen approach.

Written by the indexing model from the issue text.