Add multi-user auth, admin panel, and timezone support; rename to Yolkbook

- Rename app from Eggtracker to Yolkbook throughout
- Add JWT-based authentication (python-jose, passlib/bcrypt)
- Add users table; all data tables gain user_id FK for full data isolation
- Super admin credentials sourced from ADMIN_USERNAME/ADMIN_PASSWORD env vars,
  synced on every startup; orphaned rows auto-assigned to admin post-migration
- Login page with self-registration; JWT stored in localStorage (30-day expiry)
- Admin panel (/admin): list users, reset passwords, disable/enable, delete,
  and impersonate (Login As) with Return to Admin banner
- Settings modal (gear icon in nav): timezone selector and change password
- Timezone stored per-user; stats date windows computed in user's timezone;
  date input setToday() respects user timezone via Intl API
- migrate_v2.sql for existing single-user installs
- Auto-migration adds timezone column to users on startup
- Updated README with full setup, auth, admin, and migration docs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/main.py

@@ -1,11 +1,81 @@
+import os
+import logging
+from contextlib import asynccontextmanager
+
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from sqlalchemy import select, update, text
 
+from database import Base, engine, SessionLocal
+from models import User, EggCollection, FlockHistory, FeedPurchase, OtherPurchase
+from auth import hash_password
 from routers import eggs, flock, feed, stats, other
+from routers import auth_router, admin
 
-app = FastAPI(title="Eggtracker API")
+logger = logging.getLogger("yolkbook")
+
+
+def _seed_admin():
+    """Create or update the admin user from environment variables.
+    Also assigns any records with NULL user_id to the admin (post-migration).
+    """
+    admin_username = os.environ["ADMIN_USERNAME"]
+    admin_password = os.environ["ADMIN_PASSWORD"]
+
+    with SessionLocal() as db:
+        admin_user = db.scalars(
+            select(User).where(User.username == admin_username)
+        ).first()
+
+        if admin_user is None:
+            admin_user = User(
+                username=admin_username,
+                hashed_password=hash_password(admin_password),
+                is_admin=True,
+            )
+            db.add(admin_user)
+            db.commit()
+            db.refresh(admin_user)
+            logger.info("Admin user '%s' created.", admin_username)
+        else:
+            # Always sync password + admin flag from env vars
+            admin_user.hashed_password = hash_password(admin_password)
+            admin_user.is_admin = True
+            db.commit()
+
+        # Assign orphaned records (from pre-migration data) to admin
+        for model in [EggCollection, FlockHistory, FeedPurchase, OtherPurchase]:
+            db.execute(
+                update(model)
+                .where(model.user_id == None)  # noqa: E711
+                .values(user_id=admin_user.id)
+            )
+        db.commit()
+
+
+def _run_migrations():
+    """Apply incremental schema changes that create_all won't handle on existing tables."""
+    with SessionLocal() as db:
+        # v2.1 — timezone column on users
+        try:
+            db.execute(text(
+                "ALTER TABLE users ADD COLUMN timezone VARCHAR(64) NOT NULL DEFAULT 'UTC'"
+            ))
+            db.commit()
+        except Exception:
+            db.rollback()  # column already exists — safe to ignore
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    Base.metadata.create_all(bind=engine)
+    _run_migrations()
+    _seed_admin()
+    yield
+
+
+app = FastAPI(title="Yolkbook API", lifespan=lifespan)
 
-# Allow requests from the Nginx frontend (same host, different port internally)
 app.add_middleware(
     CORSMiddleware,
     allow_origins=["*"],
@@ -13,6 +83,8 @@ app.add_middleware(
     allow_headers=["*"],
 )
 
+app.include_router(auth_router.router)
+app.include_router(admin.router)
 app.include_router(eggs.router)
 app.include_router(flock.router)
 app.include_router(feed.router)