ZEVA 2 - Add Chat Feature for Analyst Collaboration on Credit Applications

**Describe the task**
Add a Chat feature to Credit Applications that allows analysts to communicate with each other by adding comments independently of any workflow action.
The Chat feature should be separate from the existing comment section. Currently, a comment is submitted only when a user completes an action, such as selecting Recommend, and the comment is associated with that specific action.
The new Chat feature should allow analysts to:
Add a comment without completing or submitting another action.
Add multiple comments to the same Credit Application.
View comments added by other analysts.
Edit their own existing comments.
Continue the conversation while the Credit Application remains in the analyst review stage.
The Chat feature should become read-only once the Credit Application is sent to the Director. At that stage, existing comments should remain visible, but users should not be able to add new comments or edit existing ones.

**Purpose**
Analysts need a way to communicate and collaborate while reviewing a Credit Application without having to complete a workflow action each time they want to leave a comment.
This feature will support ongoing discussion, preserve the conversation directly within the Credit Application, and clearly separate internal analyst collaboration from comments associated with formal actions such as a recommendation.

**Acceptance Criteria**
- [x] A dedicated Chat feature is available on Credit Applications during the analyst review stage.
- [x] The Chat feature is separate from the existing action-based comment section.
- [x] Analysts can add a comment without completing another action.
- [x] Multiple analysts can add comments to the same Credit Application.
- [x] Multiple comments can be displayed within the Chat feature.
- [x] Each comment clearly identifies the author and the date or time it was added, as shown in the design.
- [x] Analysts can edit comments they previously added.
- [x] Analysts cannot edit comments added by another user.
- [x] Adding or editing a Chat comment does not trigger or complete any Credit Application workflow action.
- [x] Existing action-based comments continue to work as they do today and remain associated with their respective actions.

Once the Credit Application is sent to the Director:
- [x] Existing Chat comments remain visible.
- [x] The Chat feature becomes read-only.
- [x] Users cannot add new comments.
- [x] Users cannot edit existing comments.
- [x] The analyst and Director views match the corresponding Figma designs.
- [x] The layout, controls, labels, spacing, and visual treatment match the approved design.

**Additional context**
[Refer to the Figma designs for:](https://www.figma.com/design/7Qgou3rxcHHk5qbmD9538x/ZEVA-2?node-id=3179-30523&t=nX6oBjr787VQHLoE-1)
The analyst view [before the Credit Application](https://www.figma.com/design/7Qgou3rxcHHk5qbmD9538x/ZEVA-2?node-id=3167-30272&t=nX6oBjr787VQHLoE-1) is recommended or sent to the Director.
The[ Director view,](https://www.figma.com/design/7Qgou3rxcHHk5qbmD9538x/ZEVA-2?node-id=3179-30500&t=nX6oBjr787VQHLoE-1) where the Chat feature is read-only.
This feature should not replace the existing comment section used for workflow actions.
The Chat feature is intended for internal analyst collaboration during the review process.