fix(436 B06 평면 패널): 처음 높이 바닥 160 px · 높이 상한 = 패널 % 기준 칸(offsetParent) (433-8)

- 종단 판 펼친 B06 = 칸 225 px 라 32 % 가 72 px — max(32%, 160px)
- 끌기 상한이 높이 0 인 횡단 center 를 재어 늘 120 px 로 눌림 — offsetParent 높이 − 48 px
- PLAN 436-1 검증완료

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QfHKQs7J3hQELKMWQMUJEy

resources/tester/test_258_b06_plan_peek.py

@@ -53,6 +53,7 @@ def test_높이_끌기와_기억() -> None:
     assert "createPanelResizer({" in PEEK
     assert 'cssVar: "--design-plan-peek-height",' in PEEK and "direction: 1," in PEEK
     assert 'storageKey: stateKey("plan-peek-height")' in PEEK
+    assert "max: () => (root.offsetParent?.clientHeight ?? 0) - 48," in PEEK
     assert "resizer.restore();" in PEEK[PEEK.index("const open = async") :]
     state = (ROOT / "A00_Common" / "b_page_state.ts").read_text(encoding="utf-8")
     assert '"plan-peek-height": { bucket: "pref", scope: "global" },' in state
@@ -65,7 +66,9 @@ def test_겹침_자리와_감춤() -> None:
     root = _rule(".design-plan-peek")
     assert "position: absolute;" in root and "z-index: 4;" in root
     assert "pointer-events: none;" in root  # 닫힌 동안 카드 누름 통과
-    assert "height: var(--design-plan-peek-height, 32%);" in _rule(".design-plan-peek.is-open")
+    assert "height: var(--design-plan-peek-height, max(32%, 160px));" in _rule(
+        ".design-plan-peek.is-open"
+    )
     hidden = CSS[CSS.index(".design-plan-peek .b05-routeedit__tools,") :]
     hidden = hidden[: hidden.index("}")]
     for part in ("__tools", "__info", "__measure", "__side-wrap", "b05-contourlock"):