fix: v0.7.2 语句级原子性 + 事务 DDL 拒绝 + 约束/绑定硬化 — 6 项修复 + 43 回归 + CI 重型套件串行

- UPDATE 语句级部分提交（P1，四引擎）：两阶段全量预检后执行，批内唯一互查，
  任何一行失败整句不执行（aria 场景 WAL 与内存不再错位）
- 事务内 ALTER/CREATE INDEX/DROP INDEX 残留（P1）：Memory/KVStore 显式拒绝
  （对齐 Aria），createTable/dropTable 保持可回滚
- SET NULL 级联绕过 required 约束（P1）：预检阶段整体拒绝 FOREIGN_KEY_VIOLATION
- bindParameters 注释误判（P2）：行注释/块注释中的 ? 与引号不再参与绑定
- 未闭合字符串静默接受 → lexer 抛 PARSE_ERROR；未知 where 操作符抛 QUERY_ERROR
- UPDATE undefined 覆盖列值 → 语义化为不更新（null 仍置空）
- Hybrid 写穿透非原子（P1）：磁盘失败自动重载内存对齐磁盘再抛原错误
- CI：Run tests 拆常规并行 + 重型串行（runInBand），重型测试超时余量提升，
  性能护栏 kv 120→240s / opfs 150→300s（仍拦截悬崖回归）
- 测试 1155 → 1198（74 套件），覆盖率 89.82% 保持

CONTRIBUTING.md

@@ -42,22 +42,23 @@ src/
 ├── index.ts              # Entry point, global API (MetonaSqlark + MeSqlark)
 ├── core.ts               # MetonaSqlark main class
 ├── constants.ts          # Types, defaults, enums, errors
-├── utils.ts              # Utility functions
 ├── connection-manager.ts # Connection pool (connect/disconnect)
 ├── engine/               # Storage engines
 │   ├── interface.ts      # IStorageEngine interface
 │   ├── memory.ts         # MemoryEngine (Map-based)
-│   ├── indexeddb.ts      # IndexedDBEngine (browser persistence)
-│   ├── opfs.ts           # OPFSEngine (Origin Private File System)
+│   ├── kvstore_engine.ts # KVStoreEngine (disk mode, self-built KV store)
+│   ├── kvstore/          # KVStore (log + snapshot + atomic multi-key write)
 │   └── aria/             # AriaEngine (LSM-Tree page storage engine)
 │       ├── index/        # LSM / MemTable / SSTable / Bloom / MergeIterator
 │       ├── page/         # 4KB slotted page format
 │       ├── buffer/       # Buffer Pool (LRU eviction)
 │       ├── wal/          # Write-Ahead Log + Checkpoint
 │       ├── transaction/  # MVCC manager
-│       ├── store/        # Backends (IndexedDB / OPFS / Memory)
+│       ├── store/        # Backends (OPFS / KVStore / Memory / Encrypted)
+│       ├── locks.ts      # Web Locks multi-tab exclusive lock
 │       └── compression/  # LZ4
 ├── hybrid/               # HybridEngine (write-through)
+├── migration/            # Legacy IndexedDB migration tool (one-shot)
 ├── table/                # Table management & Schema validation
 ├── query/                # Query system
 │   ├── ast.ts            # SQL AST type definitions
@@ -68,12 +69,13 @@ src/
 ├── sql/                  # SQL parser
 │   ├── tokens.ts         # Token types & keywords
 │   ├── lexer.ts          # Tokenizer
-│   └── parser.ts         # Recursive descent parser
+│   ├── parser.ts         # Recursive descent parser
+│   └── params.ts         # Parameter binding (? placeholders)
 ├── transaction/          # Transaction manager
 ├── plugin/               # Plugin system (14 lifecycle hooks)
 └── integrations/         # React & Vue hooks
 
-tests/                    # Test suite (1022 test cases, 62 suites + 7 e2e)
+tests/                    # Test suite (1198 test cases, 74 suites + 12 e2e)
 tests/helpers/             # 共享测试工具（OPFS mock 等）
 tests/e2e/                # Playwright e2e（真实 Chromium + OPFS）
 site/                     # Documentation site (index / docs / demo)