Docker + Postgres Auth Voodoo: A Troubleshooting Log of a Fatal Nano Auto-Wrap Bug

Deploying PostgreSQL with Docker, setting the correct environment variables, but still getting 'FATAL: password authentication failed'? This post documents a textbook bizarre troubleshooting journey: from a phantom password where 'two negatives make a positive,' to a persistent volume initialization blind spot, and finally tracking down a Bash variable fracture caused by the Nano editor's auto-wrap during copy-paste. A grand slam of pitfalls that every backend dev and sysadmin should be wary of.