🐛 fix(oracle): 修复DDL注释拼接缺少分号与换行

- 为 Oracle 建表 DDL 追加注释前补齐语句结束符并保留空行分隔
- 修复 COMMENT ON TABLE/COLUMN 与 CREATE TABLE 粘连导致复制后无法直接执行的问题
- 补充后端 Oracle 建表语句与前端 DDL 格式化回归测试

internal/db/oracle_get_tables_test.go

@@ -317,4 +317,7 @@ ORDER BY c.column_id`] = oracleRecordingQueryResult{
 			t.Fatalf("expected DDL to contain %q, got: %s", want, ddl)
 		}
 	}
+	if !strings.Contains(ddl, ");\n\nCOMMENT ON TABLE") {
+		t.Fatalf("expected Oracle DDL comments to be separated by a statement terminator and blank line, got: %s", ddl)
+	}
 }

internal/db/oracle_impl.go

@@ -589,7 +589,18 @@ func (o *OracleDB) appendOracleCommentDDL(baseDDL string, dbName string, tableNa
 	if len(commentLines) == 0 {
 		return baseDDL
 	}
-	return strings.TrimRight(baseDDL, " \t\r\n") + "\n" + strings.Join(commentLines, "\n")
+	return ensureOracleDDLStatementTerminator(baseDDL) + "\n\n" + strings.Join(commentLines, "\n")
+}
+
+func ensureOracleDDLStatementTerminator(ddl string) string {
+	trimmed := strings.TrimRight(ddl, " \t\r\n")
+	if trimmed == "" {
+		return trimmed
+	}
+	if strings.HasSuffix(trimmed, ";") || strings.HasSuffix(trimmed, "/") {
+		return trimmed
+	}
+	return trimmed + ";"
 }
 
 func (o *OracleDB) fetchOracleTableComment(schema string, table string) string {