Docs: Add screenshots, demo GIF, and live demo to README

[alohays]

Summary

The README is 124 lines of pure text — zero screenshots, no demo GIF, no live demo link. For a visual dashboard product with maps, real-time panels, and data visualization, this is the single biggest missed opportunity for GitHub star conversion.

Why This Matters

GitHub browsing research shows users spend 3-7 seconds scanning a README before deciding to star or leave. For visual projects, the hero image is the #1 conversion factor.

• WorldMonitor (25K+ stars, the cited inspiration): leads with visual preview
• Grafana, Uptime Kuma, Netdata: all have screenshots above the fold

Claims like "MapLibre GL + deck.gl with 5 layer types" and "6 panel types" are unverifiable without visuals. A potential user cannot imagine what this looks like.

Action Items

• Deploy a live demo on Vercel (free tier) with geopolitics-full preset (globe projection, entity tracker, instability index — most visually impressive)
• Take screenshots of 2-3 presets showing the dark-themed map with sidebar panels populated with real data
• Create a 15-second animated GIF showing: map loading → news data populating → AI brief generating → layer toggle interaction
• Add a hero image at the top of README.md, before "What is this?" section:

  <p align="center">
    <img src="docs/screenshots/hero.png" alt="monitor-forge dashboard" width="800">
  </p>

• Add a prominent "Live Demo" badge/link in the README header
• Consider adding preset-specific thumbnails to the preset comparison table

Files

• README.md — hero image, demo link, screenshot embeds
• New directory: docs/screenshots/ — hero image, preset screenshots, GIF
• Vercel deployment (operational task, not code)

Dependency

Blocked by the first-run experience fix (#2) — need a working dashboard to take screenshots from.

[alohays]

Status after PR #8

PR #8 focused on test infrastructure. No screenshots, demo, or visual assets have been added.

This remains blocked by #3 — we need a working npm run dev experience with real data before meaningful screenshots can be captured. Will revisit once the dev server API routing is resolved.