fix(timer): 分段弧光点居中置顶 + 拉大与进度弧间距

- 光点移到段中点(am=(a0+a1)/2),两端粗细对称;重构为两遍绘制,
  光点统一后绘浮于所有弧之上,不再被相邻圆头吞掉;加大加亮成珠状
- glowPad 6→18 与 _drawSetArcs pad 同步,arcR 外移 3→14,
  分段弧与进度弧间距 -1 → +10dpr(size=420),呼吸光环不重叠

components/progress-ring/progress-ring.js

@@ -105,8 +105,11 @@ Component({
 
       const cx = w / 2
       const cy = h / 2
-      // reserve room for the glowing end dot so its shadow isn't clipped
-      const glowPad = 6 * dpr
+      // Reserve room for the glowing end dot's shadow AND the outer set-progress
+      // band (circuit mode). _drawSetArcs derives its band radius from this same
+      // pad, so increasing it here also widens the gap between the countdown
+      // arc and the set band. 18dpr gives a ~10dpr visible gap (size=420).
+      const glowPad = 18 * dpr
       const radius = (size - ringWidth) / 2 * dpr - glowPad
       const lw = ringWidth * dpr
 
@@ -252,8 +255,9 @@ Component({
       const cy = (size / 2) * dpr
       // Same radius math as _draw(): the countdown arc sits at `radius`; the
       // set band wraps just outside it so the two read as concentric layers.
-      const radius = ((size - ringWidth) / 2) * dpr - 6 * dpr
-      const arcR = radius + (ringWidth / 2) * dpr + 3 * dpr
+      // NOTE: the -18*dpr pad MUST stay in sync with glowPad in _draw().
+      const radius = ((size - ringWidth) / 2) * dpr - 18 * dpr
+      const arcR = radius + (ringWidth / 2) * dpr + 14 * dpr
       const arcW = 8 * dpr
       const band = arcW / 2 + 3 * dpr
 
@@ -274,6 +278,10 @@ Component({
       const gap = (2.5 * Math.PI) / 180
       const startAngle = -Math.PI / 2
 
+      // Pass 1: draw every segment arc. Breathing dots are collected and painted
+      // in pass 2, AFTER all arcs, so a dot always floats ON TOP of its segment
+      // instead of being partially buried under neighbouring round caps.
+      const dots = []
       for (let i = 1; i <= sets; i++) {
         const a0 = startAngle + (i - 1) * segAngle + gap / 2
         const a1 = startAngle + i * segAngle - gap / 2
@@ -294,28 +302,38 @@ Component({
         ctx.stroke()
         ctx.globalAlpha = 1
 
-        // Glowing endpoint dot on the emphasized segment.
         if (emphasized) {
-          const dx = cx + arcR * Math.cos(a1)
-          const dy = cy + arcR * Math.sin(a1)
-          const dotR = (arcW / 2) * (paused ? 1 : 0.85 + 0.35 * p)
-          const glowColor = i === active ? primaryColor : successColor
-          ctx.save()
-          ctx.shadowColor = glowColor
-          ctx.shadowBlur = 8 * dpr
-          ctx.globalAlpha = paused ? 0.9 : 0.55 + 0.45 * p
-          ctx.beginPath()
-          ctx.arc(dx, dy, dotR, 0, Math.PI * 2)
-          ctx.fillStyle = glowColor
-          ctx.fill()
-          ctx.restore()
-          // white core for a "light bulb" feel
-          ctx.beginPath()
-          ctx.arc(dx, dy, dotR * 0.45, 0, Math.PI * 2)
-          ctx.fillStyle = 'rgba(255,255,255,0.85)'
-          ctx.fill()
+          const am = (a0 + a1) / 2
+          dots.push({
+            x: cx + arcR * Math.cos(am),
+            y: cy + arcR * Math.sin(am),
+            color: i === active ? primaryColor : successColor
+          })
         }
       }
+
+      // Pass 2: glowing dot on each emphasized segment, drawn over every arc.
+      // Placed at the segment MIDDLE (not the a1 end): a dot pinned to the
+      // trailing end made that end look visibly thicker than the round-cap
+      // start, so both ends of the arc stay symmetric. Slightly larger than
+      // the band width so it reads as a bead riding on top of the arc.
+      for (const dot of dots) {
+        const dotR = (arcW / 2) * (paused ? 1.3 : 1.15 + 0.25 * p)
+        ctx.save()
+        ctx.shadowColor = dot.color
+        ctx.shadowBlur = 8 * dpr
+        ctx.globalAlpha = paused ? 0.95 : 0.7 + 0.3 * p
+        ctx.beginPath()
+        ctx.arc(dot.x, dot.y, dotR, 0, Math.PI * 2)
+        ctx.fillStyle = dot.color
+        ctx.fill()
+        ctx.restore()
+        // white core for a "light bulb" feel
+        ctx.beginPath()
+        ctx.arc(dot.x, dot.y, dotR * 0.45, 0, Math.PI * 2)
+        ctx.fillStyle = 'rgba(255,255,255,0.9)'
+        ctx.fill()
+      }
     },
 
     _startSetPulse() {