to_entropy() cannot read the Japanese mnemonics to_mnemonic() writes

[fametrano]

to_entropy() cannot read the Japanese mnemonics to_mnemonic() writes. Mnemonic("japanese") joins words with U+3000, the ideographic space, as the BIP39 vectors do, but to_entropy and expand split on " " and so see a single word: to_entropy raises and expand returns the sentence unchanged. On vectors.json, to_entropy fails on all 24 Japanese mnemonics and on none of the other 264.

#110 split on self.delimiter and was reverted for failing CI. That cannot work in check, which applies NFKD first and so turns U+3000 into a plain space before splitting. This PR splits on any run of whitespace, as detect_language already does. It also makes to_seed collapse whitespace the same way, so that input check rejects, such as a trailing newline or a tab, no longer gives a different seed from the same words; if you would rather not change that, drop the to_seed line and the last assertion of test_whitespace_runs. All 288 vectors are unchanged, no input check accepts today gets a different seed, and the passphrase is not touched. Locally the tests pass on Python 3.8 to 3.14 and PyPy 3.11, and black, isort, flake8 and pyright report nothing.

Written with LLM, a computer and the Internet; the mistakes, as usual, are all mine.

[fametrano]

@prusnak could you approve the workflow run here? This is my first pull request from this fork, so CI has never started, and the local run in the description is the only evidence in the thread.

The branch is a single commit now. Since filing I added one test for expand, the fourth line the patch changes and the one that had no coverage.

[fametrano]

@prusnak the workflow runs expired before approval, so CI still hasn't run. Could you re-run them, or should I push a new commit?