Add SeedQR encoding and test

src/password_manager/seedqr.py

@@ -0,0 +1,14 @@
+"""SeedQR encoding utilities."""
+
+from __future__ import annotations
+
+from bip_utils.bip.bip39.bip39_mnemonic import Bip39Languages
+from bip_utils.bip.bip39.bip39_mnemonic_utils import Bip39WordsListGetter
+
+
+def encode_seedqr(mnemonic: str) -> str:
+    """Return SeedQR digit stream for a BIP-39 mnemonic."""
+    wordlist = Bip39WordsListGetter().GetByLanguage(Bip39Languages.ENGLISH)
+    words = mnemonic.strip().split()
+    indices = [wordlist.GetWordIdx(word.lower()) for word in words]
+    return "".join(f"{idx:04d}" for idx in indices)