feat(prediction): 工艺参数沙盘 — PI 累积曲线 + 最大速度安全区间条

预测页酸洗模型计算结果加 SVG 可视化：
- PI 累积曲线（入口零点 → 5 槽累计 PI，含目标线 dashed 标注）
- 速度安全区间条（20-180 m/min 区间内 max_speed 位置 + 数值标签）
零依赖，纯 SVG 内联。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/views/ProcessModel.vue

@@ -176,7 +176,57 @@
             </div>
           </div>
           <div v-if="calcResult.warning" class="warn-box mb12">{{ calcResult.warning }}</div>
-          <div class="sec-title">各槽酸洗详情</div>
+
+          <div class="sec-title">速度安全区间</div>
+          <div class="speed-bar-wrap">
+            <div class="speed-bar-track">
+              <div class="speed-bar-fill" :style="{ width: speedPct + '%' }"></div>
+              <div class="speed-bar-tick" style="left:0%;">20</div>
+              <div class="speed-bar-tick" style="left:100%;transform:translateX(-100%);">180</div>
+              <div class="speed-bar-marker" :style="{ left: speedPct + '%' }">
+                <div class="speed-bar-marker-label">{{ calcResult.max_speed }} m/min</div>
+              </div>
+            </div>
+          </div>
+
+          <div class="sec-title mt8">PI 累积曲线</div>
+          <svg class="pi-chart" viewBox="0 0 400 180" preserveAspectRatio="none">
+            <!-- 网格 -->
+            <g stroke="rgba(255,255,255,0.06)" stroke-width="1">
+              <line v-for="y in [0,25,50,75,100]" :key="'g'+y"
+                    x1="36" :y1="160 - y*1.3" x2="392" :y2="160 - y*1.3"/>
+            </g>
+            <!-- Y 轴刻度 -->
+            <g fill="#7a8794" font-size="9" font-family="monospace">
+              <text v-for="y in [0,25,50,75,100]" :key="'yl'+y"
+                    x="30" :y="163 - y*1.3" text-anchor="end">{{ y }}</text>
+            </g>
+            <!-- X 轴槽标签 -->
+            <g fill="#7a8794" font-size="10" font-family="monospace" text-anchor="middle">
+              <text v-for="i in 5" :key="'xl'+i" :x="36 + i*71.2" y="174">{{ i }}#</text>
+            </g>
+            <!-- 目标线 -->
+            <line :x1="36" :y1="160 - calc.target_pi*1.3" :x2="392" :y2="160 - calc.target_pi*1.3"
+                  stroke="#f0a500" stroke-width="1" stroke-dasharray="4 3"/>
+            <text :x="392" :y="160 - calc.target_pi*1.3 - 3"
+                  fill="#f0a500" font-size="9" text-anchor="end">目标 {{ calc.target_pi }}%</text>
+            <!-- 曲线 -->
+            <polyline fill="none" stroke="#00c8ff" stroke-width="2" :points="chartPoints"/>
+            <!-- 数据点 + 标签 -->
+            <g>
+              <g v-for="(pi, i) in calcResult.pi_per_tank" :key="'p'+i">
+                <circle :cx="36 + (i+1)*71.2" :cy="160 - pi*1.3" r="3.5" fill="#00c8ff"/>
+                <text :x="36 + (i+1)*71.2" :y="160 - pi*1.3 - 7"
+                      fill="#00c8ff" font-size="9" text-anchor="middle">{{ pi }}</text>
+              </g>
+            </g>
+            <!-- 入口零点 -->
+            <circle cx="36" cy="160" r="2.5" fill="#7a8794"/>
+            <polyline fill="none" stroke="#00c8ff" stroke-width="2" stroke-dasharray="2 2"
+                      :points="`36,160 ${36+71.2},${160 - calcResult.pi_per_tank[0]*1.3}`"/>
+          </svg>
+
+          <div class="sec-title mt8">各槽酸洗详情</div>
           <table class="data-table">
             <thead>
               <tr><th>酸槽</th><th>停留时间 (s)</th><th>累计PI (%)</th><th>进度</th></tr>
@@ -356,6 +406,17 @@ export default {
     acidHistory() {
       return this.calibHistory.filter(h => h.model === 'acid_speed').slice(0, 10)
     },
+    speedPct() {
+      if (!this.calcResult) return 0
+      const v = this.calcResult.max_speed
+      return Math.max(0, Math.min(100, ((v - 20) / 160) * 100))
+    },
+    chartPoints() {
+      if (!this.calcResult) return ''
+      return this.calcResult.pi_per_tank
+        .map((pi, i) => `${36 + (i+1)*71.2},${160 - pi*1.3}`)
+        .join(' ')
+    },
   },
   async mounted() {
     await this.fetchL1Data()
@@ -534,6 +595,54 @@ export default {
   border-left: 2px solid $border;
   padding-left: 8px;
 }
+.pi-chart {
+  width: 100%;
+  height: 180px;
+  display: block;
+  background: rgba(0,0,0,.18);
+  border: 1px solid $border;
+  border-radius: 4px;
+}
+.speed-bar-wrap { padding: 6px 8px 22px; }
+.speed-bar-track {
+  position: relative;
+  height: 8px;
+  background: rgba(255,255,255,.06);
+  border-radius: 4px;
+}
+.speed-bar-fill {
+  position: absolute;
+  left: 0; top: 0; bottom: 0;
+  background: linear-gradient(90deg, #28a745, #00c8ff);
+  border-radius: 4px;
+  transition: width .25s;
+}
+.speed-bar-tick {
+  position: absolute;
+  top: 12px;
+  font-size: 10px;
+  color: $text-muted;
+  font-family: monospace;
+}
+.speed-bar-marker {
+  position: absolute;
+  top: -3px;
+  width: 2px;
+  height: 14px;
+  background: #f0a500;
+  transform: translateX(-1px);
+  transition: left .25s;
+}
+.speed-bar-marker-label {
+  position: absolute;
+  top: 16px;
+  left: 50%;
+  transform: translateX(-50%);
+  font-size: 10px;
+  color: #f0a500;
+  font-family: monospace;
+  white-space: nowrap;
+}
 .calib-predict-row {
   display: flex;
   align-items: center;