feat(retrieval): 청킹/평가 하니스 + 검색 인덱스 개선

- src/retrieval/chunker.ts: 문서 청킹 로직 추가
- src/retrieval/evalHarness.ts + src/extension/evalCommands.ts: 검색 품질 평가 하니스
- brainIndex.ts / retrieval/index.ts / memoryContext.ts: 인덱싱·컨텍스트 빌더 개선
- config.ts / extension.ts / sidebarProvider.ts / package.json 갱신
- ADR-0030~0032 및 개발 기록, .astra 런타임 상태 동기화

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/contextBuilders/memoryContext.ts

@@ -7,7 +7,7 @@ import type { MemoryManager } from '../../memory';
 import type { RetrievalOrchestrator } from '../../retrieval';
 import { buildLessonChecklistBlock } from '../../retrieval/lessonHelpers';
 import { embedQuery, embedTexts } from '../../retrieval/embeddings';
-import { backfillBrainEmbeddings } from '../../retrieval/brainIndex';
+import { backfillBrainEmbeddings, backfillBrainChunkEmbeddings } from '../../retrieval/brainIndex';
 import { resolveScopeForAgent } from '../../skills/agentKnowledgeMap';
 import {
     resolveKnowledgeMix,
@@ -207,6 +207,8 @@ export async function buildMemoryContext(deps: MemoryContextDeps): Promise<strin
         embeddingBlendAlpha: config.embeddingBlendAlpha,
         workStateSignals,
         hierarchicalReweightEnabled: config.hierarchicalReweightEnabled !== false,
+        chunkLevelRetrieval: config.chunkLevelRetrieval === true,
+        chunkTargetChars: config.chunkTargetChars,
     });
 
     // Semantic Re-rank (LLM, async) — selectedChunks 의 *순서* 만 재배치. 토큰 예산을
@@ -236,12 +238,13 @@ export async function buildMemoryContext(deps: MemoryContextDeps): Promise<strin
             .map((c) => c.metadata.filePath!)
             .filter((p, i, arr) => arr.indexOf(p) === i);
         if (scoredFilePaths.length > 0) {
-            void backfillBrainEmbeddings(
-                deps.activeBrain.localBrainPath,
-                scoredFilePaths,
-                config.embeddingModel,
-                (texts) => embedTexts(texts, { baseUrl: config.ollamaUrl, model: config.embeddingModel }),
-            );
+            const embed = (texts: string[]) => embedTexts(texts, { baseUrl: config.ollamaUrl, model: config.embeddingModel });
+            // 청크 모드면 청크 단위 벡터를, 아니면 파일 단위 벡터를 채운다 (불필요한 작업 회피).
+            if (config.chunkLevelRetrieval === true) {
+                void backfillBrainChunkEmbeddings(deps.activeBrain.localBrainPath, scoredFilePaths, config.embeddingModel, embed, config.chunkTargetChars);
+            } else {
+                void backfillBrainEmbeddings(deps.activeBrain.localBrainPath, scoredFilePaths, config.embeddingModel, embed);
+            }
         }
     }