How to display and edit a One2many field in a form view as an embedded form, not a list?

I’m trying to model a one-to-one relationship between two models in Odoo.

My approach was to use a Many2one + One2many, but on the form view Odoo always displays the One2many field as a list instead of a single form.

What I need
Model A has exactly zero or one related Model B record.
Model B has exactly zero or one related Model A record.
On the form view of a Model A record, the related Model B record should appear as a single form, not as a list.

Creating or editing Model A record should allow me to directly create or edit the related single Model B record inline. By Inline, I don't mean an inline list, it should be an inline form of the single record.

Model A

class ModelA(models.Model):
    _name = 'model.a'

    b_ids = fields.One2many('model.b', 'a_id')

Model B

class ModelB(models.Model):
    _name = 'model.b'

    a_id = fields.Many2one('model.a', unique=True)