feat: update main chat and system chat UI

src/app/main/codexModelOptions.ts

@@ -0,0 +1,60 @@
+export type CodexModelOption = {
+  value: string;
+  label: string;
+  description: string;
+};
+
+export const DEFAULT_CODEX_MODEL = 'gpt-5.4';
+
+export const CODEX_MODEL_OPTIONS: CodexModelOption[] = [
+  {
+    value: 'gpt-5.4',
+    label: 'GPT-5.4',
+    description: '기본 균형형 모델',
+  },
+  {
+    value: 'gpt-5.4-mini',
+    label: 'GPT-5.4 Mini',
+    description: '빠른 응답 중심',
+  },
+  {
+    value: 'gpt-5.3-codex',
+    label: 'GPT-5.3 Codex',
+    description: '코딩 최적화',
+  },
+  {
+    value: 'gpt-5.3-codex-spark',
+    label: 'GPT-5.3 Codex Spark',
+    description: '초고속 코딩 응답',
+  },
+  {
+    value: 'gpt-5.2-codex',
+    label: 'GPT-5.2 Codex',
+    description: '안정적인 코드 작업',
+  },
+  {
+    value: 'gpt-5.1-codex-mini',
+    label: 'GPT-5.1 Codex Mini',
+    description: '가벼운 작업용',
+  },
+  {
+    value: 'gpt-5.1-codex-max',
+    label: 'GPT-5.1 Codex Max',
+    description: '깊은 추론 중심',
+  },
+];
+
+export function normalizeCodexModel(value: string | null | undefined) {
+  const normalized = value?.trim() ?? '';
+
+  if (!normalized) {
+    return DEFAULT_CODEX_MODEL;
+  }
+
+  return CODEX_MODEL_OPTIONS.some((option) => option.value === normalized) ? normalized : DEFAULT_CODEX_MODEL;
+}
+
+export function resolveCodexModelLabel(value: string | null | undefined) {
+  const normalized = normalizeCodexModel(value);
+  return CODEX_MODEL_OPTIONS.find((option) => option.value === normalized)?.label ?? normalized;
+}