feat: v0.6.1 — AriaEngine 可选自研 KVStore 后端（storageBackend: 'kv'）+ KVStore APPEND 日志类型 + 10 个 aria+kv 集成测试 + 文档全量同步

src/engine/kvstore/index.ts

@@ -223,6 +223,18 @@ export class KVStore {
     });
   }
 
+  /**
+   * v0.6.1: 追加写入（value 拼接语义）— aria WAL 分片等追加型数据用。
+   * 日志记录 APPEND 类型（O(chunk) 高效），恢复时按 seq 顺序拼接，
+   * checkpoint 后快照含最终值。崩溃时该次追加全有或全无（单记录原子）。
+   */
+  async appendValue(key: string, chunk: ArrayBuffer): Promise<void> {
+    if (chunk.byteLength === 0) return;
+    await this.enqueue(async () => {
+      await this.appendRecord({}, [], { [key]: chunk });
+    });
+  }
+
   // =======================================================================
   //  维护
   // =======================================================================
@@ -301,9 +313,13 @@ export class KVStore {
   }
 
   /** 追加一条日志记录并更新内存索引（队列内调用，无并发） */
-  private async appendRecord(puts: Record<string, ArrayBuffer>, deletes: string[]): Promise<void> {
+  private async appendRecord(
+    puts: Record<string, ArrayBuffer>,
+    deletes: string[],
+    appends: Record<string, ArrayBuffer> = {},
+  ): Promise<void> {
     this.seq++;
-    const record = encodeLogRecord(this.seq, puts, deletes);
+    const record = encodeLogRecord(this.seq, puts, deletes, appends);
     try {
       // 日志追加：介质 append（真追加）或回退读+拼+写
       const data = record.buffer.slice(record.byteOffset, record.byteOffset + record.byteLength) as ArrayBuffer;
@@ -334,6 +350,17 @@ export class KVStore {
     for (const key of deletes) {
       this.index.delete(key);
     }
+    for (const [key, chunk] of Object.entries(appends)) {
+      const existing = this.index.get(key);
+      if (existing) {
+        const combined = new Uint8Array(existing.byteLength + chunk.byteLength);
+        combined.set(new Uint8Array(existing), 0);
+        combined.set(new Uint8Array(chunk), existing.byteLength);
+        this.index.set(key, combined.buffer as ArrayBuffer);
+      } else {
+        this.index.set(key, chunk);
+      }
+    }
     this.logBytes += record.byteLength;
 
     // 自动 checkpoint（日志超阈值）
@@ -358,6 +385,16 @@ export class KVStore {
     for (const e of entries) {
       if (e.op === KVLogOp.PUT) {
         this.index.set(e.key, e.value);
+      } else if (e.op === KVLogOp.APPEND) {
+        const existing = this.index.get(e.key);
+        if (existing) {
+          const combined = new Uint8Array(existing.byteLength + e.value.byteLength);
+          combined.set(new Uint8Array(existing), 0);
+          combined.set(new Uint8Array(e.value), existing.byteLength);
+          this.index.set(e.key, combined.buffer as ArrayBuffer);
+        } else {
+          this.index.set(e.key, e.value);
+        }
       } else {
         this.index.delete(e.key);
       }

src/engine/kvstore/log.ts

@@ -23,6 +23,8 @@ import { crc32 } from '../aria/crc32';
 export const enum KVLogOp {
   PUT = 1,
   DELETE = 2,
+  /** v0.6.1: 追加写入（value 拼接语义，恢复时按序 concat；aria WAL 分片用） */
+  APPEND = 3,
 }
 
 /** 解析后的日志记录 */
@@ -40,11 +42,13 @@ export interface KVLogRecord {
  * @param seq 日志序号
  * @param puts key → value 写入条目
  * @param deletes 删除 key 列表
+ * @param appends key → 追加块列表（APPEND 语义，恢复时拼接）
  */
 export function encodeLogRecord(
   seq: number,
   puts: Record<string, ArrayBuffer>,
   deletes: string[] = [],
+  appends: Record<string, ArrayBuffer> = {},
 ): Uint8Array {
   const encoder = new TextEncoder();
   const entries: { op: KVLogOp; key: string; value: ArrayBuffer }[] = [];
@@ -54,6 +58,9 @@ export function encodeLogRecord(
   for (const key of deletes) {
     entries.push({ op: KVLogOp.DELETE, key, value: new ArrayBuffer(0) });
   }
+  for (const [key, value] of Object.entries(appends)) {
+    entries.push({ op: KVLogOp.APPEND, key, value });
+  }
 
   // 预编码 key 字节，计算总长度
   const entryBytes: { op: KVLogOp; key: Uint8Array; value: Uint8Array }[] = [];