chore: rotate default database password

[CryptoJones]

Summary

• Change the local/default Postgres password to the requested value.
• Update compose, env examples, appsettings, Python fallback, and README documentation.
• Record the change as patch release 1.11.1.

Production was rotated separately on pluto and verified over the container network.

Verification

• New password succeeds over the ApplyTrack network.
• Old password fails over the ApplyTrack network.
• API /health and /health/ready both pass after restart.
• git diff --check

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