Allow hiding MCP tool widgets in Codex App

Current behavior:
The Codex App currently shows visual MCP tool widgets such as getJiraIssue and many others in the conversation, even when project instructions explicitly say not to use or reference visual MCP widgets.

Expected behavior:
There should be a setting to hide/collapse MCP tool widgets by default, or a project/user-level option like "plain text tool output only".

Why this matters:
For Jira/Confluence/Dev workflows, the visible widgets are noisy and distract from the concise markdown summary requested by the user. Agent instructions can control the assistant's final response, but they cannot prevent the app UI from rendering the tool widget.

Example:
Calling Jira getJiraIssue for DEV-10248 displayed a noisy getJiraIssue widget even though the assistant summarized the ticket in plain markdown or even worse call the model to read over a bunch of tickets or confluence pages. The app then is going to be flooded with total unnecessary content.