Add user settings page and PWA install support

- Add profile update, password change, and account deletion endpoints
- Create Settings page with profile editing, password change, and danger zone
- Add Settings link to user dropdown menu in Layout
- Add /settings route to App.tsx
- Add API functions for profile management
- Create PWA manifest.json and add meta tags to index.html

backend/app/api/endpoints/auth.py

@@ -7,6 +7,7 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from app.core.database import get_db
 from app.core.security import hash_password, verify_password, create_access_token, get_current_user
 from app.models.user import User
+from pydantic import BaseModel, EmailStr
 from app.schemas.auth import RegisterRequest, LoginRequest, TokenResponse, UserResponse
 from app.services.spotify import get_spotify_auth_url, exchange_spotify_code, get_spotify_user
 
@@ -29,6 +30,42 @@ async def register(data: RegisterRequest, db: AsyncSession = Depends(get_db)):
     return TokenResponse(access_token=create_access_token(user.id))
 
 
+class UpdateProfileRequest(BaseModel):
+    name: str | None = None
+    email: EmailStr | None = None
+
+
+class ChangePasswordRequest(BaseModel):
+    current_password: str
+    new_password: str
+
+
+@router.put("/me")
+async def update_profile(data: UpdateProfileRequest, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)):
+    if data.name:
+        user.name = data.name
+    if data.email and data.email != user.email:
+        existing = await db.execute(select(User).where(User.email == data.email))
+        if existing.scalar_one_or_none():
+            raise HTTPException(status_code=400, detail="Email already in use")
+        user.email = data.email
+    return UserResponse(id=user.id, email=user.email, name=user.name, is_pro=user.is_pro, spotify_connected=user.spotify_id is not None)
+
+
+@router.post("/change-password")
+async def change_password(data: ChangePasswordRequest, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)):
+    if not user.hashed_password or not verify_password(data.current_password, user.hashed_password):
+        raise HTTPException(status_code=400, detail="Current password is incorrect")
+    user.hashed_password = hash_password(data.new_password)
+    return {"ok": True}
+
+
+@router.delete("/me")
+async def delete_account(user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)):
+    await db.delete(user)
+    return {"ok": True}
+
+
 @router.post("/login", response_model=TokenResponse)
 async def login(data: LoginRequest, db: AsyncSession = Depends(get_db)):
     result = await db.execute(select(User).where(User.email == data.email))