Add Marp-formatted presentation markdown for PPTX export

[Copilot]

Description

Adds Deliverables/PRESENTATION_SLIDES.md — a Marp-compatible markdown file covering the full project, exportable directly to PPTX or PDF.

19 content slides + 1 export guide slide:

• Title, agenda, project overview
• SQL vs. NoSQL comparison (problem → document model → table)
• Data modeling schema breakdown
• Three-tier architecture ASCII diagram
• Tech stack (Next.js, NestJS, MongoDB, Docker)
• API endpoints table
• Key features: search/filtering, aggregation stats, atomic $inc view counting
• Challenges & solutions table
• Scalability comparison (single-node → enterprise)
• Running the project, lessons learned, future work, Q&A
• Final slide: Marp CLI export instructions (--pptx, --pdf, --html)

Related Issue

Type of Change

• New feature
• Bug fix
• Refactoring
• Documentation

How Has This Been Tested?

File structure and Marp frontmatter validated manually. Export can be verified via marp PRESENTATION_SLIDES.md --pptx or the Marp VS Code extension.

Checklist

• Code follows project structure
• No console errors
• Tested locally
• Does not break existing features

Screenshots (if applicable)

Notes

Export commands are included at the end of the file:

npm install -g @marp-team/marp-cli
marp Deliverables/PRESENTATION_SLIDES.md --pptx --output slides.pptx