feat: 新增导入已解密目录功能，支持不走密钥流程导入已解密的数据库和资源

src/wechat_decrypt_tool/api.py

@@ -25,6 +25,7 @@ from .routers.chat_contacts import router as _chat_contacts_router
 from .routers.chat_export import router as _chat_export_router
 from .routers.chat_media import router as _chat_media_router
 from .routers.decrypt import router as _decrypt_router
+from .routers.import_decrypted import router as _import_decrypted_router
 from .routers.health import router as _health_router
 from .routers.admin import router as _admin_router
 from .routers.keys import router as _keys_router
@@ -87,6 +88,7 @@ async def _log_server_errors(request: Request, call_next):
 app.include_router(_health_router)
 app.include_router(_admin_router)
 app.include_router(_wechat_detection_router)
+app.include_router(_import_decrypted_router)
 app.include_router(_decrypt_router)
 app.include_router(_keys_router)
 app.include_router(_media_router)

src/wechat_decrypt_tool/routers/import_decrypted.py

@@ -0,0 +1,135 @@
+from __future__ import annotations
+
+import os
+import shutil
+import json
+from pathlib import Path
+from fastapi import APIRouter, HTTPException
+from pydantic import BaseModel, Field
+
+from ..app_paths import get_output_databases_dir
+from ..logging_config import get_logger
+from ..path_fix import PathFixRoute
+from ..session_last_message import build_session_last_message_table
+
+logger = get_logger(__name__)
+
+router = APIRouter(route_class=PathFixRoute)
+
+class ImportRequest(BaseModel):
+    import_path: str = Field(..., description="已解密的数据库和资源所在目录的绝对路径")
+
+def _is_valid_sqlite(path: Path) -> bool:
+    SQLITE_HEADER = b"SQLite format 3\x00"
+    try:
+        if not path.exists() or not path.is_file():
+            return False
+        with path.open("rb") as f:
+            return f.read(len(SQLITE_HEADER)) == SQLITE_HEADER
+    except Exception:
+        return False
+
+@router.post("/api/import_decrypted", summary="导入已解密的数据库和资源目录")
+async def import_decrypted_directory(request: ImportRequest):
+    """
+    导入已解密的微信数据库和资源目录。
+    该功能不需要密钥，直接将现有的已解密文件链接或复制到输出目录。
+    """
+    import_path = Path(request.import_path.strip())
+    if not import_path.exists() or not import_path.is_dir():
+        raise HTTPException(status_code=400, detail="导入路径不存在或不是目录")
+
+    # 1. 尝试识别账号名
+    # 优先从路径名识别 (例如 .../wxid_xxxx)
+    from ..wechat_decrypt import _derive_account_name_from_path
+    account_name = _derive_account_name_from_path(import_path)
+    
+    # 2. 验证关键数据库文件
+    # 必须包含 contact.db 和 session.db 才能在列表中正常显示
+    required_dbs = ["contact.db", "session.db"]
+    for db_name in required_dbs:
+        if not _is_valid_sqlite(import_path / db_name):
+            # 兼容性检查：如果不在根目录，可能在 db_storage 子目录？
+            # 但用户说“和现在完全保存的目录一致”，所以应该在根目录。
+            raise HTTPException(status_code=400, detail=f"导入目录中未找到有效的 {db_name}，请确保是已解密的扁平化目录")
+
+    # 3. 准备输出目录
+    output_base = get_output_databases_dir()
+    account_output_dir = output_base / account_name
+    account_output_dir.mkdir(parents=True, exist_ok=True)
+
+    logger.info(f"正在从 {import_path} 导入账号 {account_name} ...")
+
+    # 4. 导入 .db 文件
+    imported_files = []
+    for item in import_path.iterdir():
+        if item.is_file() and item.suffix == ".db":
+            target = account_output_dir / item.name
+            try:
+                # 优先尝试硬链接以节省空间
+                if target.exists():
+                    target.unlink()
+                os.link(item, target)
+                imported_files.append(item.name)
+            except Exception as e:
+                logger.warning(f"硬链接失败，尝试复制: {item.name}, error: {e}")
+                try:
+                    shutil.copy2(item, target)
+                    imported_files.append(item.name)
+                except Exception as e2:
+                    logger.error(f"复制失败: {item.name}, error: {e2}")
+
+    # 5. 导入 resource 目录
+    resource_src = import_path / "resource"
+    if resource_src.exists() and resource_src.is_dir():
+        resource_dst = account_output_dir / "resource"
+        try:
+            if resource_dst.exists():
+                if resource_dst.is_symlink() or resource_dst.is_file():
+                    resource_dst.unlink()
+                else:
+                    shutil.rmtree(resource_dst)
+            
+            # 对目录尝试符号链接（Windows 下可能需要权限）
+            try:
+                os.symlink(resource_src, resource_dst, target_is_directory=True)
+                logger.info("已创建 resource 目录的符号链接")
+            except Exception:
+                # 符号链接失败则尝试硬链接或复制（对于资源目录，复制比较慢，建议用户手动移动）
+                logger.warning("符号链接失败，尝试复制 resource 目录（这可能需要较长时间）")
+                shutil.copytree(resource_src, resource_dst, dirs_exist_ok=True)
+        except Exception as e:
+            logger.error(f"导入 resource 目录失败: {e}")
+
+    # 6. 保存来源信息
+    try:
+        (account_output_dir / "_source.json").write_text(
+            json.dumps(
+                {"db_storage_path": str(import_path), "import_mode": "manual_import", "imported_at": __import__('datetime').datetime.now().isoformat()},
+                ensure_ascii=False,
+                indent=2,
+            ),
+            encoding="utf-8",
+        )
+    except Exception:
+        pass
+
+    # 7. 构建缓存
+    logger.info(f"正在为 {account_name} 构建会话缓存...")
+    try:
+        build_session_last_message_table(
+            account_output_dir,
+            rebuild=True,
+            include_hidden=True,
+            include_official=True,
+        )
+    except Exception as e:
+        logger.error(f"构建会话缓存失败: {e}")
+
+    return {
+        "status": "success",
+        "account": account_name,
+        "imported_files": imported_files,
+        "has_resource": resource_src.exists(),
+        "message": f"成功导入账号 {account_name}，共 {len(imported_files)} 个数据库"
+    }