fix(pptx): import-fidelity fixes for think-cell / brand-template decks

[karthikmudunuri]

What

A batch of PPTX importer fidelity fixes found by reviewing a real brand/think-cell master template (Intero) slide-by-slide against PowerPoint. Each item was verified against the source deck and covered by a regression test.

Text

• Render run-level highlight (<a:rPr><a:highlight>) — the yellow think-cell callouts.
• Apply cap="all"/"small" as a render-time letter-case transform, including when inherited from a placeholder's list style.
• Derive font weight from weight-named families (Gilroy ExtraBold→800, … Medium→500, …) so substitute fonts render at the right heaviness.
• A shape's own <a:lstStyle> defRPr now feeds run defaults (font/size/weight) for non-placeholder text boxes.

Bullets / lists

• Map Wingdings bullet glyphs to Unicode (ü→✓, q→☐, §→▪, …).
• Repeat a character bullet across in-paragraph line breaks; suppress the glyph on empty paragraphs; trim trailing empty paragraphs (no stray blank/dash lines).
• Per-line rendering of hanging-indent bullets so multi-line items align.

Tables

• Per-cell fills, text colours, per-side borders, proportional column widths / row heights, cell spans (gridSpan/hMerge/rowSpan/vMerge), per-cell vertical anchor, and rich per-cell runs (highlight / bold / ✓ glyphs / bullet breaks). Unfilled cells stay transparent instead of inheriting a sibling's fill.

Shapes

• Skip shapes flagged hidden="1" (think-cell "do not delete" data objects).
• Synthesise block-arrow paths (down/up/left/rightArrow).
• Resolve outline colour from <p:style><a:lnRef> so dashed/outlined shapes draw.
• Keep a text-bearing shape's fill, border, and corner radius (roundRect callouts, outlined chevrons) behind the text.
• Honour <a:bodyPr><a:spAutoFit> no-wrap for short single-line labels; skip the arrow-tip text inset on no-fill label shapes.

Testing

• pnpm --filter @textcortex/slidewise test → 91 passed / 9 skipped (14 new importer regression tests in round2/roundtrip).
• pnpm typecheck clean.
• Spot-verified visually slide-by-slide against the source deck.

Notes

• Patch changeset included (.changeset/intero-import-fidelity.md).
• Remaining font-substitution differences (exact Gilroy glyph metrics) are out of scope — the deck embeds no fonts; weight is approximated.