Add: CSS Grid Island Architect quest

[Akshatshukla-25]

What does this PR do?

Closes #786

Adds CSS Grid Island Architect (quests/css-grid-architect.html) under the CSS Fundamentals category. The quest is an interactive SimCity-style urban layout game where players position city districts (skyscrapers, solar farms, parks, residential towers) onto an island matrix by writing real CSS Grid declarations (grid-template-columns, grid-template-rows, grid-area, gap, and place-items).

Type of Change

• New tool / quest
• Enhancement to existing tool
• Bug fix
• Documentation update
• Build system / infrastructure

Screenshot

Checklist

• I have read the Contributing Guide
• My branch follows the naming convention (add/tool-name, feat/description, or fix/description)
• I have tested my changes locally in at least one modern browser

For new tools / quests:

• The quest is a single self-contained .html file in the quests/ folder
• The filename is kebab-case (css-grid-architect.html)
• I added an entry to data/quests.json with all required fields
• I added a screenshot as quests/css-grid-architect.png next to the HTML file
• No JS frameworks or heavy UI libraries
• I ran node scripts/sort-norm.js data/quests.json to sort and normalize the quests registry
• I ran node scripts/build.js and verified the landing page renders correctly