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/dialect/sqlite3/sqlite3.go

@@ -5,11 +5,11 @@ import (
 	"strings"
 	"time"
 
-	"git.fsdpf.net/go/db/v2"
-	"git.fsdpf.net/go/db/v2/dialect/sqlite3"
-	"git.fsdpf.net/go/db/v2/internal/sb"
-	"git.fsdpf.net/go/db/v2/schema"
-	"git.fsdpf.net/go/db/v2/sqlgen"
+	"git.fsdpf.net/go/db"
+	"git.fsdpf.net/go/db/dialect/sqlite3"
+	"git.fsdpf.net/go/db/internal/sb"
+	"git.fsdpf.net/go/db/schema"
+	"git.fsdpf.net/go/db/sqlgen"
 )
 
 var (
@@ -72,8 +72,15 @@ func (this Sqlite3) CompileCreate(bp *schema.Blueprint) (sqls []string) {
 		}
 		columns = append(columns, sql)
 	}
+
+	prefix := "? TABLE ? (\n?\n)"
+
+	if comment := bp.Comment; comment != "" {
+		prefix = "? TABLE ? ( -- " + comment + "\n?\n)"
+	}
+
 	sqls = append(sqls,
-		this.GenerateSQL("? TABLE ? (\n?\n)",
+		this.GenerateSQL(prefix,
 			temporary,
 			db.T(bp.GetTable()),
 			db.L(strings.Join(columns, "\n")),
@@ -152,6 +159,11 @@ func (this Sqlite3) CompileRename(bp *schema.Blueprint) []string {
 	return []string{this.GenerateSQL("RENAME TABLE ? TO ?", db.T(bp.GetTable()), db.T(toName))}
 }
 
+// 修改表备注
+func (this Sqlite3) CompileModifyComment(bp *schema.Blueprint) []string {
+	return []string{}
+}
+
 func (this Sqlite3) GetColumnModifier(modifier string, bp *schema.Blueprint, column *schema.ColumnDefinition) string {
 	switch modifier {
 	case "Collate":