feat(retrieval): 接入 Note/Search/Index 服务与路由

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

backend/app/services/index_service.py

@@ -0,0 +1,69 @@
+"""索引服务：扫描 Vault、全量重建索引、查询索引状态。
+
+MVP 阶段重建是同步的（数据量小），完成后直接返回 completed 的 IndexJob。
+索引任务暂存内存（_jobs），不持久化到 SQLite；后续接入异步任务队列时再落到 index_jobs 表。
+"""
+
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from pathlib import Path
+from uuid import uuid4
+
+from app import repository
+from app.config import get_settings
+from app.contracts import IndexJob, IndexRebuildRequest, IndexStatus
+from app.knowledge.parser import parse_note
+from app.services.note_service import index_note
+from app.retrieval.vectorstore import SqliteVecStore
+
+vector_store = SqliteVecStore()
+
+_jobs: dict[str, IndexJob] = {}
+
+
+def _scan_vault() -> list[tuple[str, str, str]]:
+    """扫描 Vault 下所有 Markdown，返回 (rel_path, folder, markdown)。"""
+    vault = get_settings().vault_path
+    result: list[tuple[str, str, str]] = []
+    if not vault.exists():
+        return result
+    for path in sorted(vault.rglob("*.md")):
+        rel = path.relative_to(vault).as_posix()
+        folder = path.relative_to(vault).parent.as_posix()
+        if folder == ".":
+            folder = ""
+        result.append((rel, folder, path.read_text(encoding="utf-8")))
+    return result
+
+
+async def rebuild(request: IndexRebuildRequest) -> IndexJob:
+    job_id = "job_" + uuid4().hex[:12]
+    # MVP：scope（all/notes/vectors）与 note_ids 增量暂不区分，统一全量重建
+    repository.clear_all()
+    await vector_store.clear()
+
+    vault = get_settings().vault_path
+    for rel, folder, markdown in _scan_vault():
+        path = vault / rel
+        stat = path.stat()
+        created = datetime.fromtimestamp(stat.st_ctime, tz=timezone.utc)
+        updated = datetime.fromtimestamp(stat.st_mtime, tz=timezone.utc)
+        parsed = parse_note(
+            markdown=markdown, file_path=rel, folder=folder, tags=None,
+            created_at=created, updated_at=updated,
+        )
+        await index_note(parsed)
+
+    job = IndexJob(job_id=job_id, status="completed", scope=request.scope, created_at=datetime.now(timezone.utc))
+    _jobs[job_id] = job
+    return job
+
+
+def get_status() -> IndexStatus:
+    # 同步重建、无排队任务，因此状态恒为 idle；实际索引规模可由 GET /api/notes 与搜索反映
+    return IndexStatus(status="idle", pending_jobs=0)
+
+
+def get_job(job_id: str) -> IndexJob | None:
+    return _jobs.get(job_id)