docs(decision-lineage): expand leadership slide deck

[caohy1988]

Summary

Follow-up to #103. The original slide-deck PR was squash-merged before
the later "Bei flow" rewrite landed, so this PR carries the current
leadership deck update on top of main.

What changed:

• Reframes the deck around:
  1. Market pain
  2. Business solution
  3. Customer proof
  4. Practical demo
  5. Technical architecture
• Adds precise EU AI Act Article 99 penalty tiers and official-source
  links.
• Adds customer-proof slides with clearly marked placeholder copy.
• Expands the technical architecture appendix:
  • ADK agent + prompt contract
  • 6 campaigns x 27 plugin spans
  • AI.GENERATE BizNode MERGE
  • decision/candidate extraction write path
  • SQL-only edge derivation
  • 7 SDK backing tables
  • rich-graph projection
  • 8 node labels / 9 edge labels
  • GQL traversal and temporal audit patterns
• Tightens overclaims from "every decision / every reason" to extracted
  decisions/options/rationale.
• Fixes dense-slide layout collisions on the Article 99 and technical
  table slides.
• Regenerates checked-in SLIDES.html and SLIDES.pptx.

Test plan

• marp examples/decision_lineage_demo/SLIDES.md --html -o examples/decision_lineage_demo/SLIDES.html
• marp examples/decision_lineage_demo/SLIDES.md --html --pptx -o examples/decision_lineage_demo/SLIDES.pptx
• marp examples/decision_lineage_demo/SLIDES.md --html --pdf -o /tmp/pr104_final.pdf
• PDF has 33 pages; HTML has 33 slide sections.
• Spot-checked rendered pages for title, regulatory landscape,
  Article 99, Step 1, Step 4, Step 5, Step 6, and closing slides.
• git diff --check