feat(tui) /personality (#9718)

## Summary
Adds /personality selector in the TUI, which leverages the new core
interface in #9644

Notes:
- We are doing some of our own state management for model_info loading
here, but not sure if that's ideal. open to opinions on simpler
approach, but would like to avoid blocking on a larger refactor
- Right now, the `/personality` selector just hides when the model
doesn't support it. we can update this behavior down the line

## Testing
- [x] Tested locally
- [x] Added snapshot tests

codex-rs/tui/src/bottom_pane/selection_popup_common.rs

@@ -23,7 +23,8 @@ pub(crate) struct GenericDisplayRow {
     pub match_indices: Option<Vec<usize>>, // indices to bold (char positions)
     pub description: Option<String>,       // optional grey text after the name
     pub disabled_reason: Option<String>,   // optional disabled message
-    pub wrap_indent: Option<usize>,        // optional indent for wrapped lines
+    pub is_disabled: bool,
+    pub wrap_indent: Option<usize>, // optional indent for wrapped lines
 }
 
 pub(crate) fn wrap_styled_line<'a>(line: &'a Line<'a>, width: u16) -> Vec<Line<'a>> {
@@ -282,13 +283,18 @@ pub(crate) fn render_rows(
         }
 
         let mut full_line = build_full_line(row, desc_col);
-        if Some(i) == state.selected_idx {
+        if Some(i) == state.selected_idx && !row.is_disabled {
             // Match previous behavior: cyan + bold for the selected row.
             // Reset the style first to avoid inheriting dim from keyboard shortcuts.
             full_line.spans.iter_mut().for_each(|span| {
                 span.style = Style::default().fg(Color::Cyan).bold();
             });
         }
+        if row.is_disabled {
+            full_line.spans.iter_mut().for_each(|span| {
+                span.style = span.style.dim();
+            });
+        }
 
         // Wrap with subsequent indent aligned to the description column.
         use crate::wrapping::RtOptions;
@@ -364,11 +370,16 @@ pub(crate) fn render_rows_single_line(
         }
 
         let mut full_line = build_full_line(row, desc_col);
-        if Some(i) == state.selected_idx {
+        if Some(i) == state.selected_idx && !row.is_disabled {
             full_line.spans.iter_mut().for_each(|span| {
                 span.style = Style::default().fg(Color::Cyan).bold();
             });
         }
+        if row.is_disabled {
+            full_line.spans.iter_mut().for_each(|span| {
+                span.style = span.style.dim();
+            });
+        }
 
         let full_line = truncate_line_with_ellipsis_if_overflow(full_line, area.width as usize);
         full_line.render(