baseline: Clover 独立仓库首次基线提交

将 Clover 从上层产品包旧仓库中独立出来,建立专属版本控制。
当前状态=纵切片端到端已打通(登录→选品→出文出图→审核→下载包),
M1文案质量去套路化已验收。此提交作为后续按核销清单逐条修复的基线。

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

backend/app/api/v1/workspaces.py

@@ -0,0 +1,43 @@
+"""
+app/api/v1/workspaces.py — workspace 切换路由
+POST /workspaces/switch → /api/v1/workspaces/switch（契约路径）
+从 auth.py 独立出来，避免 /auth 前缀错误。
+"""
+
+from typing import Annotated
+
+from fastapi import APIRouter, Depends
+from pydantic import BaseModel
+from sqlalchemy.orm import Session
+
+from app.core.security import create_access_token
+from app.core.database import get_db
+from app.core.response import ok, raise_forbidden
+from app.middleware.workspace_guard import CurrentUser, get_current_user
+from app.models.workspace import WorkspaceMember
+
+router = APIRouter(tags=["workspaces"])
+
+
+class SwitchWorkspaceRequest(BaseModel):
+    workspace_id: int
+
+
+@router.post("/workspaces/switch")
+def switch_workspace(
+    body: SwitchWorkspaceRequest,
+    current_user: Annotated[CurrentUser, Depends(get_current_user)],
+    db: Session = Depends(get_db),
+):
+    """切换当前 workspace（必须查 membership 校验）。"""
+    member = db.query(WorkspaceMember).filter(
+        WorkspaceMember.user_id == current_user.user_id,
+        WorkspaceMember.workspace_id == body.workspace_id,
+    ).first()
+    if not member:
+        raise_forbidden("无权访问目标 workspace")
+    token = create_access_token(current_user.user_id, body.workspace_id, member.role)
+    return ok({
+        "current_workspace_id": body.workspace_id,
+        "token": token,
+    })