feat: add SQL Formatter tool

Summary

Add a sql-formatter.html tool that prettifies and minifies SQL queries in the browser with keyword uppercasing and consistent indentation.

Motivation

"SQL formatter online" and "SQL beautifier" are high-volume developer searches. Backend developers, data analysts, and anyone writing raw queries constantly need to clean up machine-generated or compressed SQL for readability. The Code category already has JSON, YAML, and Markdown formatters — SQL is the natural next addition.

Proposed UX

• Input / Output split pane (same layout as json-formatter.html)
• Format button: uppercase keywords, indent clauses (SELECT / FROM / WHERE / JOIN / GROUP BY / ORDER BY / HAVING / LIMIT each on their own line with consistent indentation), align AND/OR under WHERE
• Minify button: collapse to a single line, single-space separated
• Dialect selector: Standard SQL · MySQL · PostgreSQL · SQLite · T-SQL (affects keyword set and quoting style — backtick vs double-quote identifiers)
• Indentation control: 2 spaces / 4 spaces / tab
• Keyword case toggle: UPPERCASE / lowercase / Capitalize
• Copy output · Download .sql · Clear

Implementation notes

• Category: Code
• Slug: sql-formatter
• Icon: 🗄️
• Library: sql-formatter (MIT, ~100 KB) — well-maintained, supports all major dialects, has an ESM build. Use sibling-module pattern (sql-formatter.js) for the bare-specifier import.
• Follow src/_tool-template.html and run bun run generate:sections, bun run generate:index, bun run generate:favicon after adding to tools.json

Start with src/_tool-template.html and json-formatter.html, then inspect tools.json and the sibling-module pattern for the sql-formatter.js import. Add the sql-formatter tool with the specified formatting, minifying, dialect, indentation, case, copy, download, and clear controls, then run bun run generate:sections, bun run generate:index, and bun run generate:favicon.