feat(models): offer Opus 5.5 in the model picker and task routing (#480)

Adds claude-opus-5-5 to the App Settings model picker (base option with
data-ctx="1" plus its [1m] companion row, since Opus 5.5 has a 1M window)
and to the five task-routing selects, mirroring how Fable 5.1 was added.

Co-authored-by: Claude <noreply@anthropic.com>

test/app-settings-structure.test.ts

@@ -123,7 +123,13 @@ describe('App Settings modal structure', () => {
     const select = modal.match(/id="appSettingsClaudeModel"([\s\S]*?)<\/select>/)?.[1] ?? '';
     // The cards render the base models; the [1m] rows exist so that base + the
     // context switch can compose back into a real claudeModel value.
-    for (const value of ['opus[1m]', 'claude-fable-5[1m]', 'claude-fable-5-1[1m]', 'claude-opus-4-6[1m]']) {
+    for (const value of [
+      'opus[1m]',
+      'claude-fable-5[1m]',
+      'claude-fable-5-1[1m]',
+      'claude-opus-5-5[1m]',
+      'claude-opus-4-6[1m]',
+    ]) {
       expect(select).toContain(`value="${value}"`);
     }
     expect(select).toContain('data-ctx="1"');
@@ -148,6 +154,22 @@ describe('App Settings modal structure', () => {
     }
   });
 
+  it('models: offers Opus 5.5 as a card and to task routing', () => {
+    const modal = settingsModal();
+    const select = modal.match(/id="appSettingsClaudeModel"([\s\S]*?)<\/select>/)?.[1] ?? '';
+    expect(select).toMatch(/value="claude-opus-5-5"[^>]*data-ctx="1"/);
+    for (const id of [
+      'appSettingsDefaultModel',
+      'appSettingsModelExplore',
+      'appSettingsModelImplement',
+      'appSettingsModelTest',
+      'appSettingsModelReview',
+    ]) {
+      const routing = modal.match(new RegExp(`id="${id}"([\\s\\S]*?)</select>`))?.[1] ?? '';
+      expect(routing, `${id} does not offer Opus 5.5`).toContain('value="claude-opus-5-5"');
+    }
+  });
+
   it('has retired the modal-tab chrome everywhere, not just here', () => {
     // Session Options and Add Case moved onto this same `set-*` surface, so the
     // old tab classes have no users left. A reappearance means a modal drifted