Convert delete_nonreduced_fuzz_inputs.sh to rust

[ekzyis]

This converts the existing bash script to rust as suggested in #268 (comment).

Also updated README and added this to the documentation in the script:

Also, it's recommended to run the script twice to ensure that the results are "somewhat" reproducible.

How I tested this:

1. Setup ubuntu 24.04 vm with virt-manager and 8GiB allocated memory on NixOS
2. Run these commands:

$ git clone --branch rust-delete-nonreduced-fuzz-inputs https://github.com/ekzyis/qa-assets
$ cp -r qa-assets/delete-nonreduced-fuzz-inputs .
$ cd delete-nonreduced-fuzz-inputs
$ sudo apt install cargo
$ sudo cargo run -Znext-lockfile-bump

3. Listen to computer sounds for over 1 hour
4. Check if expected git commits have been created

[ekzyis]

fd99a28 First successful complete run deleted 6k files and took 1h10min:

$ find all_inputs -type f | wc -l
122591
$ find qa-assets/fuzz_corpora -type f | wc -l
116419

commit aa0c651d8ae39db2e71c0f8a7c7d2af4b7ef648c
Author: delete_nonreduced_inputs script <noreply@noreply.noreply>
Date:   Mon Mar 30 00:44:05 2026 +0000

    Reduced inputs for fuzzer,address,undefined,integer

commit 4b90c7119a1d6eb8b8a300db1c95464d8c02abb8
Author: delete_nonreduced_inputs script <noreply@noreply.noreply>
Date:   Mon Mar 30 00:06:47 2026 +0000

    Reduced inputs for fuzzer

commit 9ddd4d8a1f44e47e6c03c24e29587d82ab73fd59
Author: delete_nonreduced_inputs script <noreply@noreply.noreply>
Date:   Sun Mar 29 23:53:35 2026 +0000

    Reduced inputs for afl-cmin

commit e73b464051a4b1c1a92eb550518da72cdb08ea8d
Author: delete_nonreduced_inputs script <noreply@noreply.noreply>
Date:   Sun Mar 29 23:36:52 2026 +0000

    Delete fuzz inputs

commit bdc226d2037713aac729e047c4e3521f56f45b98
Author: Niklas Gögge <n.goeggi@gmail.com>
Date:   Fri Mar 13 16:44:07 2026 +0100

    Merge pull request #263 from maflcko/main
    
     Delete nonreduced fuzz inputs

Will run again tomorrow, but I think this is ready for review now

[maflcko]

lgtm. Thx

Just left some nits, some of which are unrelated, none of which are a blocker.

Going to merge for now, but the nits can be addressed in a follow-up, if they make sense.

[ekzyis]

Addressed the feedback in #270, thank you for the review and merge!