feat(memory): add experimental qmd search backend

src/daemon/memory.ts

@@ -1,8 +1,9 @@
 import type { Config } from '../config/index.js';
 import type { Lifecycle } from './lifecycle.js';
 import { MemoryStore } from '../memory/index.js';
-import { VectorStore, HybridSearch, createEmbeddingProvider, chunkText, contentHash } from '../memory/index.js';
+import { VectorStore, HybridSearch, QmdSearch, createEmbeddingProvider, chunkText, contentHash } from '../memory/index.js';
 import type { EmbeddingProvider as EmbeddingProviderInterface } from '../memory/index.js';
+import type { MemorySearchBackend } from '../tools/builtin/memory-search.js';
 import { createMemoryTools } from '../tools/builtin/index.js';
 import type { ToolRegistry } from '../tools/index.js';
 import { resolve } from 'path';
@@ -17,7 +18,7 @@ export interface MemoryDeps {
 
 export interface MemoryResult {
   memoryStore?: MemoryStore;
-  hybridSearch?: HybridSearch;
+  searchBackend?: MemorySearchBackend;
   memoryDir: string;
 }
 
@@ -32,18 +33,19 @@ export async function initMemory(deps: MemoryDeps): Promise<MemoryResult> {
     : undefined;
 
   // Register memory tools if memory is enabled
-  let hybridSearch: HybridSearch | undefined;
+  let searchBackend: MemorySearchBackend | undefined;
 
   if (memoryStore && config.memory.embedding.enabled) {
     try {
       const embeddingProvider: EmbeddingProviderInterface = createEmbeddingProvider(config.memory.embedding);
       const vectorStore = new VectorStore(resolve(dataDir, 'vectors.db'));
-      hybridSearch = new HybridSearch(
+      const hybridSearch = new HybridSearch(
         memoryStore,
         vectorStore,
         embeddingProvider,
         config.memory.embedding.hybrid_weight,
       );
+      searchBackend = hybridSearch;
 
       // Background indexer: re-embed dirty namespaces every 30 seconds
       const indexerInterval = setInterval(async () => {
@@ -89,11 +91,19 @@ export async function initMemory(deps: MemoryDeps): Promise<MemoryResult> {
     }
   }
 
+  if (!searchBackend && memoryStore && config.memory.qmd.enabled) {
+    searchBackend = new QmdSearch(memoryStore, {
+      topK: config.memory.qmd.top_k,
+      minScore: config.memory.qmd.min_score,
+    });
+    console.log(`QMD memory search enabled (top_k=${config.memory.qmd.top_k}, min_score=${config.memory.qmd.min_score})`);
+  }
+
   if (memoryStore) {
-    for (const tool of createMemoryTools(memoryStore, hybridSearch)) {
+    for (const tool of createMemoryTools(memoryStore, searchBackend)) {
       toolRegistry.register(tool);
     }
   }
 
-  return { memoryStore, hybridSearch, memoryDir };
+  return { memoryStore, searchBackend, memoryDir };
 }