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/schema.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"sync"
 
-	"git.fsdpf.net/go/db/v2"
+	"git.fsdpf.net/go/db"
 )
 
 type Schema interface {
@@ -27,6 +27,8 @@ type Schema interface {
 	CompileDropColumn(bp *Blueprint) []string
 	// 表重命名
 	CompileRename(bp *Blueprint) []string
+	// 修改表备注
+	CompileModifyComment(bp *Blueprint) []string
 	// 生成SQL
 	GenerateSQL(sql string, args ...any) string
 }