feat(training): 新增握力环 2.0 摄像头手势识别页

用前置摄像头 + VisionKit/ROI 管线驱动开合计数，复用跟练舞台与连击粒子，并加固结束收尾避免末段卡死无响应。

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

TUICallKit-Vue3/training/motion/openness.ts

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+import type { HandSample, Point2D } from './types'
+
+/** VisionKit 文档：1=布/开掌，3=握拳 */
+const GESTURE_OPEN = 1
+const GESTURE_FIST = 3
+
+/**
+ * OpenPose-21 指尖索引（相对手腕距离用于连续 openness）
+ * 0 wrist, 4 thumb tip, 8 index, 12 middle, 16 ring, 20 pinky
+ */
+const TIP_INDEXES = [4, 8, 12, 16, 20]
+
+function dist(a: Point2D, b: Point2D) {
+    const dx = a.x - b.x
+    const dy = a.y - b.y
+    return Math.sqrt(dx * dx + dy * dy)
+}
+
+function clamp01(v: number) {
+    return Math.max(0, Math.min(1, v))
+}
+
+/** 离散手势 → 开合度；未知手势返回 null（交给几何或保持） */
+export function opennessFromGesture(gesture?: number): number | null {
+    if (gesture === GESTURE_OPEN) return 1
+    if (gesture === GESTURE_FIST) return 0
+    return null
+}
+
+/**
+ * 用指尖到手腕的平均距离 / 掌宽 估计 openness。
+ * 握力环场景开合幅度偏小，映射区间比裸掌更紧一些。
+ */
+export function opennessFromLandmarks(points?: Point2D[]): number | null {
+    if (!points || points.length < 21) return null
+    const wrist = points[0]
+    const mcpIndex = points[5]
+    const mcpPinky = points[17]
+    const palmWidth = dist(mcpIndex, mcpPinky)
+    if (palmWidth < 1e-6) return null
+
+    let tipSum = 0
+    for (const i of TIP_INDEXES) {
+        tipSum += dist(points[i], wrist)
+    }
+    const tipMean = tipSum / TIP_INDEXES.length
+    // 握力环：握紧约 0.9~1.35 掌宽，半开约 1.5~2.2 掌宽
+    const ratio = tipMean / palmWidth
+    return clamp01((ratio - 0.95) / 1.15)
+}
+
+export function mergeOpenness(sample: Pick<HandSample, 'gesture' | 'points'>): number | null {
+    const fromGeom = opennessFromLandmarks(sample.points)
+    const fromGesture = opennessFromGesture(sample.gesture)
+
+    if (fromGeom != null && fromGesture != null) {
+        // 几何为主：离散手势（布/拳）在捏环时容易误判，只做轻牵引
+        return clamp01(fromGeom * 0.85 + fromGesture * 0.15)
+    }
+    if (fromGeom != null) return fromGeom
+    if (fromGesture != null) return fromGesture
+    return null
+}