feat(view): 형상계획 ② screen skeleton with five members (plan.md C1)

- ① and ② are switched from the stage nav. ② shows the pier list with change
  counts, the five members (교량받침, 코핑, 기둥, 확대기초·말뚝, 지반·지층) with
  a change count each, a member card, and a change list with per-item revert.
- The member card shows 기본 and 선택 summaries separately. Only members with
  existing inputs get fields (코핑 폭·길이, 말뚝 길이); the others show values
  and a note that their inputs come in a later step. Unselected members' inputs
  are not shown.
- The field rows are shared between ① and ②.
- Added a global [hidden] rule so hidden screens stay hidden.
- Not verified in a browser.

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

src/style.css

@@ -652,3 +652,15 @@ body { background: #eef1f4; font-family: 'Noto Sans KR', system-ui, sans-serif;
 .chk.disabled { opacity: 0.5; }
 #cp-preview td, #cp-preview th { font-size: 12px; }
 
+/* 형상계획 ② (plan.md C1) */
+[hidden] { display: none !important; }
+.members { list-style: none; padding: 0; margin: 0; }
+.members li { margin: 2px 0; }
+.members-title { margin-top: 14px; }
+.member { display: flex; align-items: center; justify-content: space-between; gap: 8px; width: 100%; min-height: 44px; padding: 0 10px; border: 0; border-radius: 6px; background: transparent; color: #18212b; font-size: 13px; text-align: left; cursor: pointer; }
+.member[aria-pressed='true'] { background: #e3edf8; color: #123e70; font-weight: 700; }
+#member-fields { margin-top: 10px; }
+#member-summary { color: #55606e; margin: 4px 0 8px; }
+.plan .viewer { flex: 1 1 380px; }
+.plan .results { flex: 1 1 300px; max-width: 360px; }
+