feat: add SQL format button with keyword uppercasing and clause line breaks

[aalvaropc]

Summary

• New SqlFormatter module that formats SQL with uppercased keywords, clause-level line breaks, and indented sub-clauses
• "Format" button in the SQL editor toolbar
• Handles SELECT, FROM, WHERE, JOIN, GROUP BY, ORDER BY, HAVING, LIMIT, and other major clauses
• Normalizes whitespace and indents sub-clauses (JOIN, AND, OR, ON) for readability
• Updates both the LiveView state and CodeMirror editor content via set_sql event

Test plan

• mix test test/onesqlx/querying/sql_formatter_test.exs — 7 tests (keywords, line breaks, JOINs, GROUP BY, whitespace)
• mix precommit — 638 tests, 0 failures
• Manual: type messy SQL, click Format, verify clean output in editor