Strip advisory identifiers (GHSA-*) from describe blocks, test
docblocks, and inline comments. Replace with plain descriptive
labels. Also clean up FQCNs to use imported class names and minor
style fixes (string concatenation spacing).
Replace direct shell interpolation of environment values with base64 encoding
to prevent command injection attacks. Environment configuration is now built as
a single string, base64-encoded, then decoded to file atomically.
Also add regex validation to restrict environment field values to safe
characters (alphanumeric, underscore, hyphen, dot) at the application layer.
Fixes GHSA-3xm2-hqg8-4m2p
