style: satisfy the black gate that was failing the Tests workflow

The Tests workflow was red on every OS and Python version for one reason:
`black --check` found 28 unformatted files. Part predates this branch (the
tui_v3 screens, core/api.py, core/index0.py); part is mine from this session.

Formatting only — verified rather than assumed, because a formatter touching
363 files is exactly where an unnoticed behaviour change would hide:

  - 1223 Python tests pass, unchanged
  - regenerating the fixtures after reformatting the generator produces
    byte-identical output, so no hashed value moved
  - differential fuzz: no divergences

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01Vtx94nXDmNgXEeThUZP4QN

scripts/generate_test_profile.py

@@ -45,6 +45,8 @@ def test_app_dir() -> Path:
     another ``tests`` segment on each reload.
     """
     return Path(consts.APP_DIR) / "tests"
+
+
 from utils.key_derivation import derive_key_from_password, derive_index_key
 from seedpass.core.encryption import EncryptionManager
 from seedpass.core.vault import Vault