Fix entrypoint: use printenv for hyphenated INPUT_* vars

[baylesj]

Problem

GitHub Actions passes Docker action inputs with hyphens preserved in the env var name — e.g. INPUT_OUTPUT-SVG, not INPUT_OUTPUT_SVG. Bash cannot reference hyphenated variable names with ${} syntax, so those values were silently empty and --output-svg was never passed to the binary.

The ASCII terminal report still printed (it goes to stdout regardless), but no SVG file was written, so git-auto-commit-action found nothing to commit.

Fix

Read the hyphenated env vars via printenv 'INPUT_OUTPUT-SVG' etc., store them in local bash variables, then build the arg array from those.

Test plan

• Re-run the profile repo action after this image is built — wrote gerrit-heatmap.svg should appear in the step log
• git-auto-commit-action commits the file

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