Code editor layout: Karpathy toggle, CSS grid layout, AI panel fixes

- 🧠 Karpathy 코딩 가이드라인 토글 버튼 추가 (시스템 프롬프트 주입)
- 모델 셀렉터를 AI 패널 헤더 내부로 이동 (채팅창 너비 연동)
- CSS Grid 레이아웃으로 전환: AI 패널이 파일 탭 상단까지 연장
- 오른쪽 공백 수정: auto 컬럼 → CSS 변수(--ai-panel-w) 제어
- 입력창 소실 수정: #code-ai-panel에 overflow:hidden 추가
- 터미널 불작동 수정: .code-bottom-panels overflow:hidden 제거
- body padding/gap 초기화로 전체 여백 제거

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web-ui/styles.css

@@ -2358,12 +2358,18 @@
 /* ── Code Editor View ────────────────────────────────────────── */
 #code-view {
   display: none;
-  flex-direction: column;
   height: 100%;
   background: var(--bg);
   overflow: hidden;
 }
-#code-view.active { display: flex; }
+#code-view.active {
+  display: grid;
+  grid-template-columns: 1fr 5px var(--ai-panel-w, 360px);
+  grid-template-rows: 1fr auto;
+  grid-template-areas:
+    "editor vresize ai"
+    "term   term    term";
+}
 .code-tabs-bar {
   display: flex;
   align-items: flex-start;
@@ -2417,22 +2423,33 @@
 .code-tool-btn.btn-save    { background:#0d1f2e; border-color:#1a4a6b; color:#60a5fa; }
 .code-tool-btn.primary     { background:#166534; border-color:#22c55e; color:#fff; }
 .code-tool-btn.primary.busy { background:#7f1d1d; border-color:#ef4444; }
-.code-body {
-  display: flex; flex: 1; min-height: 0; overflow: hidden;
+.code-editor-col {
+  grid-area: editor;
+  display: flex;
+  flex-direction: column;
+  min-width: 0;
+  overflow: hidden;
 }
 #code-editor-container {
   flex: 1; min-width: 0; position: relative; background: #1e1e1e;
 }
 .code-vresize {
+  grid-area: vresize;
   width: 5px; cursor: col-resize; background: #333; flex-shrink: 0;
   transition: background .15s;
 }
 .code-vresize:hover { background: #3b78ff; }
 #code-ai-panel {
-  width: 360px; min-width: 220px; max-width: 60%;
+  grid-area: ai;
+  min-width: 220px;
   display: flex; flex-direction: column;
   background: #080f0c; border-left: 1px solid #1a3a28;
-  flex-shrink: 0;
+  overflow: hidden;
+}
+.code-bottom-panels {
+  grid-area: term;
+  display: flex;
+  flex-direction: column;
 }
 .code-ai-header {
   display: flex; align-items: center; justify-content: space-between;
@@ -2673,6 +2690,9 @@
   cursor: pointer;
   padding-right: 20px;
   color-scheme: dark;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
 }
 .csb-model-select-wrap select option {
   background: #1a2a1a;