Switch reasoning, mode, plan, and fast from the Command Center (#2274)

* Switch reasoning, mode, plan, and fast from the Command Center

Extend the Command Center (Cmd-K) with selectors for a focused agent's
Thinking (reasoning effort), access Mode, Plan mode, and Fast mode,
mirroring the model switcher. Typing surfaces tiered "<Setting> › <Value>"
breadcrumb rows with icons and a check on the current value, for both a
running agent and a new draft tab. Rows only appear while typing, so the
default palette is unchanged.

- Thinking and Mode are multi-option selects; Plan mode and Fast mode are
  On/Off toggles.
- Plan mode is dual-natured: a permission mode for Claude/Copilot/OpenCode
  (excluded from the Mode list, given its own toggle) and the plan_mode
  feature for Codex. Fast mode drives the fast_mode feature (model-gated).
- All logic lives in command-center/agent-setting-contributions.ts as pure,
  unit-tested builders, with a small icon helper and a hook that registers
  the running-agent selectors; the draft registers from its composer tab.
  No changes to the command palette component and no protocol changes.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* Unify Command Center agent controls

* refactor: clarify agent control ownership

* refactor(app): tighten command center agent controls

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: Mohamed Boudra <boudra.moha@gmail.com>

packages/app/src/command-center/command-center.tsx

@@ -401,6 +401,15 @@ interface ResultRowProps {
 
 const ResultRow = memo(function ResultRow({ result, active, onSelect }: ResultRowProps) {
   const press = useCallback(() => onSelect(result), [onSelect, result]);
+  const choice =
+    result.kind === "contribution" && result.contribution.presentation.kind === "choice"
+      ? result.contribution.presentation
+      : null;
+  const accessibilityLabel = choice?.path.join(" › ");
+  const accessibilityState = useMemo(
+    () => (isNative && choice ? { selected: choice.selected } : undefined),
+    [choice],
+  );
   const style = useCallback(
     ({ hovered, pressed }: PressableStateCallbackType & { hovered?: boolean }) => [
       styles.row,
@@ -415,7 +424,15 @@ const ResultRow = memo(function ResultRow({ result, active, onSelect }: ResultRo
     [active, result],
   );
   return (
-    <Pressable style={style} onPress={press}>
+    <Pressable
+      style={style}
+      onPress={press}
+      accessibilityRole="button"
+      accessibilityLabel={accessibilityLabel}
+      accessibilityState={accessibilityState}
+      aria-pressed={isWeb ? choice?.selected : undefined}
+      testID={choice?.testId}
+    >
       <ResultContent result={result} />
     </Pressable>
   );
@@ -497,7 +514,7 @@ function ResultContent({ result }: { result: CommandCenterResult }) {
     );
   }
   return (
-    <View style={styles.rowContent} testID={presentation.testId}>
+    <View style={styles.rowContent}>
       <View style={styles.rowMain}>
         {Icon ? (
           <View style={styles.iconSlot}>