SQL Query Challenge

[rhalbhavi]

What does this PR do?

This PR adds a new SQL Query Challenge Quest.

This quest teaches fundamental and advanced SQL querying skills. The gameplay hook is an interactive challenge where users write SQL queries to transform input data tables into specific, expected output tables. It provides immediate visual feedback, allowing for rapid, hands-on learning.

The category of this quest is General Dev Quests.

Key Features

• Write SQL queries in a browser-based editor.
• Compare your query output against the target table in real-time.
• Multiple levels of increasing difficulty, from basic SELECT to complex JOINs.
• Progress is saved locally in the browser via the LocalStorage API.
• Client-side execution using SQL.js, so it works entirely offline.

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Closes #438

Type of Change

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

Screenshot

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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:

• The tool is a single self-contained .html file in the tools/ folder
• The filename is kebab-case (e.g. json-formatter.html)
• I added an entry to data/tools.json with all required fields
• I added a screenshot as tools/<tool-name>.png next to the HTML file
• No JS frameworks (React, Vue, Angular, etc.) or heavy UI libraries (Bootstrap JS, jQuery, etc.)
• CDN links for lightweight libraries and fonts are fine — no copy-pasting library source code inline
• I ran node scripts/sort-norm.js data/tools.json to sort and normalize the tools registry
• I ran node scripts/build.js and verified the landing page renders correctly

For enhancements / bug fixes:

• I have not introduced any external dependencies
• The tool still works as a standalone single HTML file

[praveenscience]

Since you didn't rebase - this time I'm reducing the points from Medium to Easy.

[praveenscience]

Next time, try to commit only the relevant files into the branch.