v1.2.9: 라이브 에디터·홈 피드·메인 커버 개선

라이브 모드 코드/콜아웃/토글 편집, 슬래시 명령, 홈 Latest List·Compact·Cards 보기,
사이트 설정 메인 화면 커버(720px) 및 HomeHero 반영.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/textarea-caret-coordinates.js

@@ -0,0 +1,82 @@
+/**
+ * textarea 커서 위치의 박스 기준 좌표를 계산한다(미러 div 방식).
+ * @param {HTMLTextAreaElement} textarea - 대상 textarea
+ * @param {number} position - 문자 인덱스
+ * @returns {{ top: number, left: number, height: number }} top·left·line height(px)
+ */
+export const getTextareaCaretCoordinates = (textarea, position) => {
+  const style = window.getComputedStyle(textarea)
+  const mirror = document.createElement('div')
+
+  mirror.setAttribute('aria-hidden', 'true')
+  mirror.style.position = 'absolute'
+  mirror.style.visibility = 'hidden'
+  mirror.style.whiteSpace = 'pre-wrap'
+  mirror.style.wordWrap = 'break-word'
+  mirror.style.overflow = 'hidden'
+
+  const properties = [
+    'direction',
+    'boxSizing',
+    'width',
+    'height',
+    'overflowX',
+    'overflowY',
+    'borderTopWidth',
+    'borderRightWidth',
+    'borderBottomWidth',
+    'borderLeftWidth',
+    'paddingTop',
+    'paddingRight',
+    'paddingBottom',
+    'paddingLeft',
+    'fontStyle',
+    'fontVariant',
+    'fontWeight',
+    'fontStretch',
+    'fontSize',
+    'lineHeight',
+    'fontFamily',
+    'textAlign',
+    'textTransform',
+    'textIndent',
+    'textDecoration',
+    'letterSpacing',
+    'wordSpacing',
+    'tabSize'
+  ]
+
+  for (const property of properties) {
+    mirror.style[property] = style[property]
+  }
+
+  const isBoxSizingBorderBox = style.boxSizing === 'border-box'
+  const width = isBoxSizingBorderBox
+    ? textarea.offsetWidth
+    : textarea.offsetWidth
+      - parseFloat(style.borderLeftWidth)
+      - parseFloat(style.borderRightWidth)
+      - parseFloat(style.paddingLeft)
+      - parseFloat(style.paddingRight)
+
+  mirror.style.width = `${width}px`
+
+  const value = textarea.value
+  const before = value.slice(0, position)
+  const after = value.slice(position) || '.'
+
+  mirror.textContent = before
+  const marker = document.createElement('span')
+  marker.textContent = after
+  mirror.appendChild(marker)
+
+  document.body.appendChild(mirror)
+
+  const top = marker.offsetTop + parseFloat(style.borderTopWidth) + parseFloat(style.paddingTop)
+  const left = marker.offsetLeft + parseFloat(style.borderLeftWidth) + parseFloat(style.paddingLeft)
+  const height = parseFloat(style.lineHeight) || marker.offsetHeight || 0
+
+  document.body.removeChild(mirror)
+
+  return { top, left, height }
+}