feat(codex): add GPT-5.6 model catalog

Closes #1633

src/cliproxy/model-catalog.ts

@@ -190,6 +190,42 @@ export const MODEL_CATALOG: Partial<Record<CLIProxyProvider, ProviderCatalog>> =
     displayName: 'Copilot Codex',
     defaultModel: 'gpt-5.4',
     models: [
+      {
+        id: 'gpt-5.6-sol',
+        name: 'GPT-5.6 Sol',
+        description: 'Latest frontier agentic coding model.',
+        thinking: {
+          type: 'levels',
+          levels: ['low', 'medium', 'high', 'xhigh'],
+          maxLevel: 'xhigh',
+          dynamicAllowed: false,
+        },
+        codexServiceTiers: ['fast'],
+      },
+      {
+        id: 'gpt-5.6-terra',
+        name: 'GPT-5.6 Terra',
+        description: 'Balanced agentic coding model for everyday work.',
+        thinking: {
+          type: 'levels',
+          levels: ['low', 'medium', 'high', 'xhigh'],
+          maxLevel: 'xhigh',
+          dynamicAllowed: false,
+        },
+        codexServiceTiers: ['fast'],
+      },
+      {
+        id: 'gpt-5.6-luna',
+        name: 'GPT-5.6 Luna',
+        description: 'Fast and affordable agentic coding model.',
+        thinking: {
+          type: 'levels',
+          levels: ['low', 'medium', 'high', 'xhigh'],
+          maxLevel: 'xhigh',
+          dynamicAllowed: false,
+        },
+        codexServiceTiers: ['fast'],
+      },
       {
         id: 'gpt-5.5',
         name: 'GPT-5.5',