feat: add example gallery with auto-generated screenshots (#253)

* feat: add script to generate 300x300 grid-cell.png screenshots for examples

- Add generate-grid-screenshots.spec.ts Playwright test to capture screenshots
- Add npm run generate:screenshots command (Docker-based for Santa compatibility)
- Add sharp dependency for image resizing with centered-fill mode
- Generate grid-cell.png for 14 example servers (only React for basic-server-* series)

The screenshots are 300x300 PNG images cropped with centered fill mode,
suitable for use in a grid layout showcasing the examples.

* docs: add example gallery grid to README

Add a 3-column visual grid showcasing 14 example MCP Apps with:
- Thumbnail screenshots (300x300 grid-cell.png)
- Clickable links to example directories
- Hover tooltips with brief descriptions

Organized by visual impact: 3D/WebGL examples first, then
visualizations, charts, monitoring, and starter templates.

* fix: use aspect-fit instead of crop for screenshots

Change from fit: 'cover' (crops) to fit: 'contain' (letterbox)
so the full app content is visible without cropping.

* feat: improve screenshot generation

- Constrain viewport to 500px width for consistent rendering
- Wait 5 seconds for full app load (tiles, animations, data)
- Screenshot just the inner iframe (no extra whitespace)
- Save both screenshot.png (full-size) and grid-cell.png (300x300 thumbnail)
- Use contain mode to preserve aspect ratio

* fix: use cover mode with top alignment for grid thumbnails

No letterboxing - crops to fill 300x300, aligned to top so headers
and important content are always visible.

* feat: improve screenshot gallery

- Remove integration-server from gallery (it's for E2E testing only)
- Add 30s extra wait for Map and Video servers to load fully
- Improve Three.js default scene: isometric rotation + better lighting
- Update README: Starter Templates row with links to all framework variants
  (React, Vue, Svelte, Preact, Solid, Vanilla JS)
- Regenerate all screenshots with updated settings

* fix: improve README gallery layout

- Fix uneven column widths by using minimal separator
- Move Starter Templates to separate 2-cell table with description
- Add screenshot.png to top of each example README (13 examples)
- Shorten tooltips for cleaner table

* revert to document.write again; cesiumjs doesn't like srcdoc, period.

* fix: map-server screenshot now renders properly

- Merged ochafik/post-fixes which reverts sandbox from srcdoc to document.write
  (CesiumJS doesn't work with srcdoc iframes)
- Fixed map-server name in screenshot test ('Map Server' not 'CesiumJS Map Server')
- Simplified screenshot generation script (removed complex debugging code)
- Increased map-server wait time to 45s for reliable tile loading
- Regenerated all 13 screenshots

* fix: remove redundant screenshots from READMEs

Remove the simple \![Screenshot](screenshot.png) line from READMEs that
already had nicer HTML table screenshots. Keep it only for examples
that didn't have existing screenshots.

* docs: move gallery to Examples section

- Move screenshot gallery from top of README to Examples section
- Remove redundant list of basic examples (now shown visually in gallery)
- Clean up duplicate run instructions

* fix: remove empty header row from starter templates table

* fix: remove empty header rows from both tables

* fix: add prettier-ignore to prevent table header expansion

* feat: use custom screenshot for video-resource-server

- Use better screenshot from PR #253 comment showing actual video playback
- Skip video-resource-server in screenshot generation script
- Add SKIP_SERVERS set for manually maintained screenshots

* fix: revert unrelated map-server name change

* fix: use correct server name 'CesiumJS Map Server' in screenshot test

package.json

@@ -64,6 +64,7 @@
     "prepare": "node scripts/setup-bun.mjs && npm run build && husky",
     "docs": "typedoc",
     "docs:watch": "typedoc --watch",
+    "generate:screenshots": "docker run --rm -v $(pwd):/work -w /work mcr.microsoft.com/playwright:v1.57.0-noble sh -c 'npm i -g bun && npm ci && npx playwright test tests/e2e/generate-grid-screenshots.spec.ts'",
     "prettier": "prettier -u \"**/*.{js,jsx,ts,tsx,mjs,json,md,yml,yaml}\" --check",
     "prettier:fix": "prettier -u \"**/*.{js,jsx,ts,tsx,mjs,json,md,yml,yaml}\" --write",
     "check:versions": "node scripts/check-versions.mjs"
@@ -85,6 +86,7 @@
     "prettier": "^3.6.2",
     "react": "^19.2.0",
     "react-dom": "^19.2.0",
+    "sharp": "^0.34.5",
     "ts-to-zod": "^5.1.0",
     "tsx": "^4.21.0",
     "typedoc": "^0.28.14",