Improve table UX and fix MySQL 8.0 bug

[antarr]

Summary

• SQL syntax highlighting in all table views (dark Catppuccin Mocha theme with keyword/function/string/number coloring)
• Redesigned table headers (uppercase, thicker borders, rounded corners)
• Row hover states with blue tint, cleaner alternating row colors
• Right-aligned numeric columns with monospace tabular-nums
• Duration values color-coded green/amber/red by severity
• Tab persistence across page reloads via URL hash
• Fix unused indexes SQL error on MySQL 8.0+ (reads/writes are reserved words)

Test plan

• 71 examples, 0 failures
• RuboCop clean
• Visual check: Query Stats tab SQL rendering
• Visual check: Table Sizes numeric alignment
• Visual check: Tab persists after page reload
• Verify unused indexes tab works on MySQL 8.0+