fix: Use whole-line match for alembic empty migration check The previous `grep -ic pass` matched "pass" as a case-insensitive substring, so column names like `password_hash` would be counted. This caused false negatives where a non-empty migration with 2 "password" columns would pass the check. Use `grep -cE '^\s+pass$'` to only match actual Python `pass` statements. Refs mayetrx/trak#584