Add interactive refinement capability to Field Widget Actions
## Summary
Add support for interactive refinement in ai_automators Field Widget Action plugins, allowing users to iteratively improve AI-generated content through conversational prompts before accepting it into a field. This is the companion issue to https://www.drupal.org/project/field_widget_actions/issues/3547306, which adds the modal infrastructure. This issue covers wiring up the automator plugins to use it.
## Problem
Field Widget Actions automate content generation, but once content is generated there is no way to refine it without manually editing or re-running the entire automator. Once the field_widget_actions module ships `RefinementAwareInterface` and the refinable suggestions modal, automator plugins in this module will need to implement that interface before the feature is usable end-to-end.
Site builders who configure automators on text and taxonomy fields would benefit directly.
## Proposed solution
Implement `RefinementAwareInterface` from `field_widget_actions` in the relevant automator plugins:
- `Text` — text and string fields
- `ClassificationOptionsSelect` — taxonomy select fields
- `AutoCompleteTagsTaxonomy` — autocomplete tags fields
- `Email`, `ImageAltText`, `ImageFilename`, `ListString`, `SummaryTextareaWithSummary`
Add a shared `RefinementTrait` providing the AJAX refinement loop: reading the refinement prompt from the request, re-running the automator with the combined original constraints + refinement instruction, and returning updated modal content.
**Depends on:** field_widget_actions MR https://git.drupalcode.org/issue/field_widget_actions-3547306/-/merge_requests/19
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