feat: v0.6 分割树架构——横梃竖梃完整编辑

- 逆向确认原站设计思路: 基底多边形+mm.sp分割树(polyId指向作用区域),
  运行时重放得到最终窗格(254套样本验证重放语义)
- 前端 replayShape: 分割树重放还原真实网格(平开1矩形→4-7格)
- 中梃编辑: 点击选中高亮/拖动移动/删除(直接操作sp源真值后重放)
- 加梃升级: polyId.idx 精确指向被点窗格
- Python报价算料同语义重放: 中梃长度精确到实际作用跨度
- 方案文档§3.3: 原站设计思路+编辑器完成设计

frontend/src/types/drawing.ts

@@ -119,3 +119,93 @@ export function bboxOf(points: Pt[]): { x0: number; y0: number; x1: number; y1:
   const ys = points.map(p => p.y)
   return { x0: Math.min(...xs), y0: Math.min(...ys), x1: Math.max(...xs), y1: Math.max(...ys) }
 }
+
+/** 分割线轴向: v=竖梃(恒定x) h=横梃(恒定y) */
+export function spAxis(sp: SplitLine): 'v' | 'h' {
+  const n = sp.line?.norm ?? { x: 1, y: 0 }
+  return Math.abs(n.x) >= Math.abs(n.y) ? 'v' : 'h'
+}
+
+export function spPos(sp: SplitLine): number {
+  return spAxis(sp) === 'v' ? sp.line.pt.x : sp.line.pt.y
+}
+
+/**
+ * 分割树重放（逆向自原站 shapeManager 的分割模型）:
+ * polygon.polygon 为基底多边形, mm.sp[] 为分割树 — 每条 sp 通过 polyId.idx 指向
+ * 其作用区域, 按顺序应用后得到最终窗格。重放时:
+ * - idx 越界/为-1 → 作用于基底区域0
+ * - 分割坐标落在目标区域边上(退化)或目标非凸 → 跳过(no-op), 该梃按目标bbox裁剪绘制
+ */
+export function replayShape(shape: FrameShape): {
+  regions: Segment[][]
+  clips: { sp: SplitLine; bb: { x0: number; y0: number; x1: number; y1: number } }[]
+} {
+  const base = (shape.polygon?.polygon ?? []).map(r => r.map(s => ({ ps: { ...s.ps }, pe: { ...s.pe } })))
+  const regions: Segment[][] = base.map(r => r)
+  const clips: { sp: SplitLine; bb: { x0: number; y0: number; x1: number; y1: number } }[] = []
+  for (const sp of (shape.mm?.sp ?? []) as SplitLine[]) {
+    if (!sp?.line?.pt || !sp.line.norm) continue
+    const axis = spAxis(sp)
+    const pos = spPos(sp)
+    let idx = sp.polyId?.idx ?? -1
+    if (!Number.isInteger(idx) || idx < 0 || idx >= regions.length) idx = 0
+    const target = regions[idx]
+    if (!target || target.length < 3) { continue }
+    const bb = bboxOf(regionPoints(target))
+    const lo = axis === 'v' ? bb.x0 : bb.y0
+    const hi = axis === 'v' ? bb.x1 : bb.y1
+    if (pos <= lo + 0.5 || pos >= hi - 0.5) {
+      clips.push({ sp, bb })   // 退化: 边线上的记录, 仅用于绘制
+      continue
+    }
+    const split = splitPolySegments(target, axis, pos)
+    if (!split) { clips.push({ sp, bb }); continue }
+    regions.splice(idx, 1, split.a, split.b)
+    clips.push({ sp, bb })
+  }
+  return { regions, clips }
+}
+
+/** 两次交叉点法分割闭合多边形段链(凸区域), 失败返回 null */
+export function splitPolySegments(region: Segment[], axis: 'v' | 'h', pos: number):
+  { a: Segment[]; b: Segment[] } | null {
+  const pts = regionPoints(region)
+  const n = pts.length
+  const get = (p: Pt) => (axis === 'v' ? p.x : p.y)
+  const crossings: { i: number; p: Pt }[] = []
+  for (let i = 0; i < n; i++) {
+    const a = pts[i], b = pts[(i + 1) % n]
+    const da = get(a) - pos, db = get(b) - pos
+    if ((da < 0 && db > 0) || (da > 0 && db < 0)) {
+      const t = da / (da - db)
+      crossings.push({
+        i,
+        p: axis === 'v'
+          ? { x: pos, y: a.y + (b.y - a.y) * t }
+          : { x: a.x + (b.x - a.x) * t, y: pos },
+      })
+    }
+  }
+  if (crossings.length !== 2) return null
+  const [c1, c2] = crossings
+  if (c1.i === c2.i) return null
+  const collect = (from: typeof c1, to: typeof c2): Pt[] => {
+    const ps: Pt[] = [from.p]
+    for (let k = (from.i + 1) % n; ; k = (k + 1) % n) {
+      ps.push(pts[k])
+      if (k === to.i) break
+    }
+    ps.push(to.p)
+    return ps.filter((p, i) => i === 0 || Math.abs(p.x - ps[i - 1].x) > 0.01 || Math.abs(p.y - ps[i - 1].y) > 0.01)
+  }
+  const toSegs = (ps: Pt[]): Segment[] => {
+    const segs: Segment[] = []
+    for (let i = 0; i < ps.length; i++) segs.push({ ps: ps[i], pe: ps[(i + 1) % ps.length], name: 'segment' })
+    return segs
+  }
+  const polyA = collect(c1, c2)
+  const polyB = collect(c2, c1)
+  if (polyA.length < 3 || polyB.length < 3) return null
+  return { a: toSegs(polyA), b: toSegs(polyB) }
+}