fix: harden 'make help' for shell portability

[lengau]

I believe this fixes #538

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[Copilot]

Pull request overview

This PR updates the shared help make target implementation to be more portable under /bin/sh (and to avoid the quoting/EOF failure reported in #538) when generating the target help listing.

Changes:

• Refactors the help recipe into a single-line awk program to avoid multi-line quoting issues under /bin/sh.
• Suppresses command echoing for the separator line and makes the makefile list ordering more robust by falling back when tac is unavailable.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.