feat: harden auth and study workflows

- replace plaintext login and unlock requests with RSA-OAEP/AES-GCM encrypted payloads

- add login challenge replay protection, production RSA key validation, and auth tests

- wire compose to environment-driven dev/prod settings without committing local secrets

- update setup-config smoke scripts and Postman docs for encrypted login

- add visit schedule migrations/tests and update study/subject setup workflows

backend/app/api/v1/auth.py

@@ -1,12 +1,13 @@
 from datetime import datetime, timedelta, timezone
 from fastapi import APIRouter, Depends, HTTPException, status
 from fastapi import File, UploadFile
-from pydantic import BaseModel, EmailStr, Field
+from pydantic import BaseModel, Field
 from sqlalchemy.ext.asyncio import AsyncSession
 from pathlib import Path
 import uuid
 
 from app.core.config import settings
+from app.core.login_crypto import create_login_challenge, decrypt_login_payload, get_public_key_pem
 from app.core.security import create_access_token, decode_token_allow_expired, oauth2_scheme, verify_password
 from app.core.deps import get_current_user, get_db_session
 from app.crud import user as user_crud
@@ -16,8 +17,16 @@ from fastapi.responses import FileResponse
 
 
 class LoginRequest(BaseModel):
-    email: EmailStr
-    password: str = Field(min_length=1)
+    key_id: str = Field(min_length=1)
+    challenge: str = Field(min_length=16)
+    ciphertext: str = Field(min_length=1)
+
+
+class LoginKeyResponse(BaseModel):
+    key_id: str
+    public_key: str
+    challenge: str
+    expires_at: datetime
 
 
 class ExtendResponse(BaseModel):
@@ -25,9 +34,8 @@ class ExtendResponse(BaseModel):
     expiresAt: datetime
 
 
-class UnlockRequest(BaseModel):
-    email: EmailStr
-    password: str = Field(min_length=1)
+class UnlockRequest(LoginRequest):
+    pass
 
 
 class UnlockResponse(BaseModel):
@@ -40,6 +48,42 @@ AVATAR_ROOT = Path(__file__).resolve().parent.parent.parent / "uploads" / "avata
 AVATAR_ROOT.mkdir(parents=True, exist_ok=True)
 
 
+def issue_user_token(db_user) -> Token:
+    session_start = datetime.now(timezone.utc)
+    access_token = create_access_token(
+        user_id=str(db_user.id),
+        role=db_user.role.value if hasattr(db_user.role, "value") else db_user.role,
+        expires_minutes=None,
+        session_start=session_start,
+    )
+    return Token(access_token=access_token, token_type="bearer")
+
+
+async def authenticate_encrypted_password(payload: LoginRequest, db: AsyncSession):
+    decrypted = decrypt_login_payload(
+        key_id=payload.key_id,
+        challenge=payload.challenge,
+        ciphertext=payload.ciphertext,
+    )
+    if not decrypted:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="无法验证登录凭据",
+        )
+    db_user = await user_crud.get_by_email(db, decrypted.email)
+    if not db_user:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="账号不存在",
+        )
+    if not verify_password(decrypted.password, db_user.password_hash):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="密码错误",
+        )
+    return db_user
+
+
 @router.post("/register", status_code=status.HTTP_201_CREATED)
 async def register(
     payload: UserRegisterRequest,
@@ -54,35 +98,29 @@ async def register(
     return {"message": "注册成功，等待管理员审核"}
 
 
+@router.get("/login-key", response_model=LoginKeyResponse)
+async def get_login_key() -> LoginKeyResponse:
+    challenge = create_login_challenge()
+    return LoginKeyResponse(
+        key_id=settings.LOGIN_RSA_KEY_ID,
+        public_key=get_public_key_pem(),
+        challenge=challenge.value,
+        expires_at=challenge.expires_at,
+    )
+
+
 @router.post("/login", response_model=Token)
 async def login_for_access_token(
     payload: LoginRequest, db: AsyncSession = Depends(get_db_session)
 ) -> Token:
-    db_user = await user_crud.get_by_email(db, payload.email)
-    if not db_user:
-        raise HTTPException(
-            status_code=status.HTTP_401_UNAUTHORIZED,
-            detail="账号不存在",
-        )
-    if not verify_password(payload.password, db_user.password_hash):
-        raise HTTPException(
-            status_code=status.HTTP_401_UNAUTHORIZED,
-            detail="密码错误",
-        )
+    db_user = await authenticate_encrypted_password(payload, db)
     if db_user.status != UserStatus.ACTIVE:
         raise HTTPException(
             status_code=status.HTTP_401_UNAUTHORIZED,
             detail="账号未审核或不可用",
         )
 
-    session_start = datetime.now(timezone.utc)
-    access_token = create_access_token(
-        user_id=str(db_user.id),
-        role=db_user.role.value if hasattr(db_user.role, "value") else db_user.role,
-        expires_minutes=None,
-        session_start=session_start,
-    )
-    return Token(access_token=access_token, token_type="bearer")
+    return issue_user_token(db_user)
 
 
 @router.get("/me", response_model=UserRead)
@@ -133,11 +171,7 @@ async def unlock_session(
     payload: UnlockRequest,
     db: AsyncSession = Depends(get_db_session),
 ) -> UnlockResponse:
-    db_user = await user_crud.get_by_email(db, payload.email)
-    if not db_user:
-        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="账号不存在")
-    if not verify_password(payload.password, db_user.password_hash):
-        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="密码错误")
+    db_user = await authenticate_encrypted_password(payload, db)
     if db_user.status != UserStatus.ACTIVE:
         raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="账号已停用")
     session_start = datetime.now(timezone.utc)