Verify: placeholder line limits (title/subtitle) + overflow warnings

[tmustier]

Verify: placeholder line limits (title/subtitle) + agent-friendly overflow warnings

Problem

Agents often produce titles/subtitles that wrap beyond the intended placeholder height (e.g. title slide subtitle becomes 2 lines and overlaps the next placeholder). Without visual verification, these issues slip through.

Proposed direction

• Make max-line limits template-config driven (e.g. title max 2 lines; title-slide subtitle max 1 line)
• Emit clear warnings during:
  • pptx generate (when YAML provides title/subtitle metadata)
  • pptx edit / pptx batch (when editing placeholders)

Warnings should:

• say which slide/placeholder
• estimate wrapped line count
• state max allowed
• suggest making text more concise (and later: optionally suggest reducing font size for body overflow)

Notes

• This is a warning system (no hard failure by default) to keep agent loops smooth.
• Long-term: consider a deck-level pptx verify-deck that checks overlaps and placeholder overflows after all edits.

Acceptance criteria

• Template config supports max-lines for title/subtitle placeholders
• pptx edit warns when title/subtitle likely exceed max lines
• pptx generate warns when YAML title/subtitle likely exceed max lines
• Works without requiring PowerPoint rendering