feat(projects): add dedicated og-image for projects page

- Add generate-projects-og.js script to create og-image with category icons
- Renders at 1920x1008 and downscales to 1200x630 for crisp icons
- Features collage of VS, VS Code, GitHub, NuGet, CLI, and desktop icons
- Add npm script: cover:projects-og
- Update projects listing page to use custom og-image

Author: CalvinAllen

package.json

@@ -12,6 +12,7 @@
     "new:project": "node scripts/new-project.js",
     "cover": "node scripts/generate-cover.js",
     "cover:project": "node scripts/generate-project-cover.js",
+    "cover:projects-og": "node scripts/generate-projects-og.js",
     "copy-originals": "node scripts/copy-originals.js",
     "fetch:stats": "node scripts/fetch-project-stats.js"
   },