[Bug]: Unexpected Behavior using the vcol of AutoAPI

[MichaelDecent]

Describe the Bug

Declared a table field with vcol (virtual column) but column ended up being create on the database

Steps to Reproduce

1. Declaring a a table field using vcol :

@alias_ctx(create="add", read="get", list="browse")
class Book(Base):
    __tablename__ = "books"
     
   ...
    # Virtual, read-only derived field
    slug: Mapped[str] = vcol(
        field=F(py_type=str, constraints={"max_length": 256}),
        io=IO(out_verbs=("read","list")),
        read_producer=lambda obj, ctx: f"{(obj.title or '').strip().lower().replace(' ','-')}-{(obj.author or '').strip().lower().replace(' ','-')}"
    )

2. Make a Create api request call.
3. Results to a SQL related error

Software Version

<0.4.0

Python Version

Python 3.8

Environment Details

No response

Relevant Logs or Error Output

{
  "detail": "<class 'sqlalchemy.exc.IntegrityError'>: (sqlite3.IntegrityError) NOT NULL constraint failed: books.slug\n[SQL: INSERT INTO books (title, author, price, published_at, slug) VALUES (?, ?, ?, ?, ?)]\n[parameters: ('string', 'string', 0.0, None, None)]\n(Background on this error at: https://sqlalche.me/e/20/gkpj)"
}

Additional Context (Optional)

No response

Confirmation

• I have searched the existing issues for this bug.
• I have provided all necessary information to reproduce the bug.