Standardize unicode characters

# Is your feature request related to a problem? Please describe.
Unicode characters are literal characters or escape sequences in different places.

# Describe the solution you'd like
Pick one and make everything in the repo use it. CI should enforce it.

No files, tests, or entry points are named. First inventory where Unicode appears as literal characters versus escape sequences, then decide on one repository-wide convention and determine how CI can enforce it. Done means the convention is applied consistently and CI rejects deviations.

Written by the indexing model from the issue text.