feat: initial MVP - FastAPI backend + Vue3 frontend + docker-compose

- backend: FastAPI + SQLAlchemy 2.0(async) + asyncpg + Alembic
- 7 API routes: auth/me/articles/sources/bookmarks/subscriptions/admin
- models: User/Source/Article/Bookmark/Subscription/ApiToken
- services: RSS fetcher (feedparser) + Tencent TMT translator with quota + cache + local NLLB fallback
- workers: APScheduler + asyncio pipeline (fetch -> dedupe -> insert -> translate)
- seed scripts: create_user, seed_sources (5 RSS: Reuters/BBC/Al Jazeera/NHK/DW)
- frontend: Vue 3 + Vite + Naive UI + Pinia + vue-router
- pages: Login, Feed (24h), ArticleDetail, Sources, Bookmarks, AdminSources
- deploy: docker-compose (postgres/redis/api/worker/frontend/caddy)
- docs: README, DEPLOY, architecture, acceptance

backend/app/schemas/auth.py

@@ -0,0 +1,20 @@
+"""Auth schemas."""
+from __future__ import annotations
+
+from pydantic import BaseModel, Field
+
+
+class LoginRequest(BaseModel):
+    username: str = Field(min_length=1, max_length=64)
+    password: str = Field(min_length=6, max_length=128)
+
+
+class TokenPair(BaseModel):
+    access_token: str
+    refresh_token: str
+    token_type: str = "bearer"
+    expires_in: int  # seconds
+
+
+class RefreshRequest(BaseModel):
+    refresh_token: str