feat(tui) /permissions flow (#9561)

## Summary
Adds the `/permissions` command, with a (usually) shorter set of
permissions. `/approvals` still exists, for backwards compatibility.

<img width="863" height="309" alt="Screenshot 2026-01-20 at 4 12 51 PM"
src="https://github.com/user-attachments/assets/c49b5ba5-bc47-46dd-9067-e1a5670328fe"
/>


## Testing
- [x] updated unit tests
- [x] Tested locally

codex-rs/common/src/approval_presets.rs

@@ -24,21 +24,21 @@ pub fn builtin_approval_presets() -> Vec<ApprovalPreset> {
         ApprovalPreset {
             id: "read-only",
             label: "Read Only",
-            description: "Requires approval to edit files and run commands.",
+            description: "Codex can read files in the current workspace. Approval is required to edit files or access the internet.",
             approval: AskForApproval::OnRequest,
             sandbox: SandboxPolicy::ReadOnly,
         },
         ApprovalPreset {
             id: "auto",
-            label: "Agent",
-            description: "Read and edit files, and run commands.",
+            label: "Default",
+            description: "Codex can read and edit files in the current workspace, and run commands. Approval is required to access the internet or edit other files. (Identical to Agent mode)",
             approval: AskForApproval::OnRequest,
             sandbox: SandboxPolicy::new_workspace_write_policy(),
         },
         ApprovalPreset {
             id: "full-access",
-            label: "Agent (full access)",
-            description: "Codex can edit files outside this workspace and run commands with network access. Exercise caution when using.",
+            label: "Full Access",
+            description: "Codex can edit files outside this workspace and access the internet without asking for approval. Exercise caution when using.",
             approval: AskForApproval::Never,
             sandbox: SandboxPolicy::DangerFullAccess,
         },