docs: Add CLAUDE.md with codebase guidance

Create comprehensive documentation for future Claude Code instances working in this repository, including:
- Development commands for testing, building, and code quality
- Core architecture overview of the SQL query builder system
- Directory structure and component explanations
- Testing patterns and conventions
- Key dependencies and their purposes

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

schema/util.go

@@ -1,26 +1,8 @@
 package schema
 
-import (
-	"strings"
-
-	"github.com/samber/lo"
-)
-
 func PrefixArray(prefix string, values []string) (items []string) {
 	for _, value := range values {
 		items = append(items, prefix+" "+value)
 	}
 	return items
 }
-
-func QuoteString(value any) string {
-	switch v := value.(type) {
-	case []string:
-		return strings.Join(lo.Map(v, func(item string, _ int) string {
-			return "'" + item + "'"
-		}), ", ")
-	case string:
-		return "'" + v + "'"
-	}
-	return ""
-}