figure-agent v0.1.7.2

Cleanup release closing the v0.1.6-era pending bugfix.

CHANGELOG v0.1.6 flagged a stray no-extension file that "occasionally appears in exports/" after a /fig_export pass, with the suspected root cause being svg_to_png.sh passing a no-suffix output to rsvg-convert. Reproduction confirmed: both rsvg-convert and pdftocairo -svg write to the exact path given, so a caller (LLM following /fig_export, hand-typed shell) that drops .png or .svg silently produces a stray file the user has to rm manually.

Fixed

• scripts/svg_to_png.sh: reject output paths that do not end with .png with a clear stderr message.
• scripts/export_svg.sh: same defense for .svg outputs.
• tests/test_export_svg.py (new) and an additional case in tests/test_svg_to_png.py lock the suffix guards against regression.

Verified

• 110 pytest pass (108 → 110), ruff clean.
• Live export sanity (proper-suffix paths still work end-to-end on smoke_trap_demo).