fix: schema_compat 跳过不存在的表，避免 columnPatch 对缺失表 panic

Co-Authored-By: claude-flow <ruv@ruv.net>

initialize/schema_compat.go

@@ -138,6 +138,14 @@ func EnsureSchemaCompatibility(ctx *svc.ServiceContext) error {
 	}
 
 	for _, patch := range columnPatches {
+		tblExists, err := tableExists(ctx.DB, patch.table)
+		if err != nil {
+			return errors.Wrapf(err, "check table %s failed", patch.table)
+		}
+		if !tblExists {
+			logger.Infof("[SchemaCompat] skipping column patch %s.%s: table does not exist", patch.table, patch.column)
+			continue
+		}
 		exists, err := columnExists(ctx.DB, patch.table, patch.column)
 		if err != nil {
 			return errors.Wrapf(err, "check column %s.%s failed", patch.table, patch.column)