Add Apex OTP importer

Import TOTP credentials from the export spreadsheet into a VivoKey Apex
OTP (ykneo-oath) applet over PC/SC. Includes the OATH protocol layer
(SELECT/VALIDATE/LIST/PUT with 61xx reassembly), PBKDF2 password
authentication, pre-flight input validation, ask-per-conflict handling,
optional javacard-memory profiling, and hardware-free unit tests.

.gitignore

@@ -0,0 +1,24 @@
+# Never commit OTP secrets, exports, or profiling logs.
+*.xlsx
+*.xls
+*.csv
+otp-keys-export.*
+apex-otp-memlog.csv
+
+# QR screenshots / backup codes, in case any data is placed in the repo tree.
+*.png
+*.jpg
+*_backup_codes.txt
+*-backup-codes.txt
+*recovery*.txt
+
+# Python
+__pycache__/
+*.pyc
+*.pyo
+.venv/
+venv/
+.pytest_cache/
+
+# CAP artifacts
+*.cap