The PPTX table branch read `el.outline.width` without a guard, so a slide
table stored without an `outline` threw a TypeError and failed the whole
PPTX (and resource pack) export with a generic "export failed" toast. The
slide renderer already treats the outline as optional; the exporter now
does too and simply omits the border.
Claude-Session: https://claude.ai/code/session_01H5k2jng7f8wbobbMX8Tdwx
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>