coderabbit: Fix single-quoted strings with intended expansions

[marcusquinn]

Finding #5: Single-quoted strings with intended expansions

Evidence:
SC2016 flags across supervisor-archived/*, generate-claude-commands.sh and others.

Risk:
Variables not expanded as intended; confusing behavior for maintainers.

Recommended Action:
Where variable interpolation is intended, switch to double quotes; otherwise add a comment or a local shellcheck disable if truly literal:

# Instead of: echo 'User: $name'
echo "User: $name"

# Or if truly literal:
# shellcheck disable=SC2016 # intended literal for documentation
echo 'User: $name'

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Source: #2386

[github-actions]

Completed via PR #2426. merged to main.