fix: improve pptx slide fidelity

[developer0hye]

What changed

• preserve fixed textbox no-wrap titles and ordered-list markers
• restore missing slide 20 and slide 30 content, including EMF-backed images
• fix grouped PPTX shape handling for hidden line extensions so white icon backgrounds stay white
• improve fixed textbox and connector layout fidelity across affected slides

Why

• several PPTX slides diverged materially from PowerPoint output, including wrapped headings, missing numbering, missing imagery, mispositioned connectors, compressed table content, and incorrect icon background fills

Key changes

• parser fixes for color/style resolution, group/vector image handling, table geometry, and extension skipping
• renderer fixes for no-wrap text boxes, ordered list marker layout, connector rotation, and auto-fit behavior
• regression coverage for the slide-specific shape, table, and textbox cases

Relevant context

• validated against the internal PPTX fixture by regenerating PDF output and checking the affected slides

Related: #100, #101, #103, #111