CngxFormBridge

Lets cngx's value-bearing form atoms take part in Angular Reactive Forms exactly like a native <input>: put [formControl] / [formControlName] on the atom and its value flows into form.value, with validation, disabled and touched wired for free. Without it a cngx-toggle or cngx-multi-chip-group would be inert to reactive forms.

This is the single ControlValueAccessor in cngx - it auto-applies by selector (you never reference cngxFormBridge yourself) and talks to the host through CNGX_CONTROL_VALUE, keeping the atoms themselves Forms-agnostic.

Covers, in both element and attribute form: cngx-toggle, cngx-checkbox, cngx-radio-group, cngx-checkbox-group, cngx-button-toggle-group, cngx-button-multi-toggle-group, cngx-chip-group, cngx-multi-chip-group, and [cngxChipInteraction] (attribute only). Signal Forms ([field]) and the Level-3 select controls bypass this entirely - they provide CNGX_FORM_FIELD_CONTROL directly. To bridge a bare self-contained external/Material CVA control into a cngx field, see CngxBindField.

Behaviour:

• All four CVA hooks wrap their bodies in untracked(). Load-bearing on registerOnChange: the effect reads control.value() then invokes fn(value) outside the dependency graph, so any signal fn touches (today via RF internals, tomorrow via signal-based RF) does not feed back into the effect.
• registerOnChange skips its first run - initial value is delivered via writeValue per CVA contract.
• writeValue stamps lastSeen; the change-listener short-circuits on Object.is so the RF→atom→RF round-trip never re-emits.

<!-- No bridge directive to add: it auto-attaches via selector to each atom below. -->
<form [formGroup]="form">
  <cngx-toggle formControlName="notifications" />
  <cngx-multi-chip-group formControlName="tags">
    @for (t of pool; track t) {
      <cngx-chip cngxChipInGroup [value]="t">{{ t }}</cngx-chip>
    }
  </cngx-multi-chip-group>
</form>
<!-- form.value is now { notifications: boolean; tags: string[] } -->