feat(linkage): 移动改为任意入口位置选择，仅上卷鞍座触发生产

- 计划新增 position 字段；新增 /plan/{id}/move?position=… 与 /plan/positions/all
- line_service.place_at_position：放到任意位置(位置唯一占用)，上卷鞍座单独触发生产联动
- 入口跟踪：新增入口位置图(单一鞍座)显示占位；移动按钮弹出位置选择框
- 计划管理：移动按钮同样弹出位置选择框

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/Plan.vue

@@ -78,8 +78,8 @@
               <td><span :class="['badge', statusBadge(row.status)]">{{ statusLabel(row.status) }}</span></td>
               <td @click.stop>
                 <span class="action-link" @click="openDialog(row)">编辑</span>
-                <span v-if="row.status === 'online'"
-                      class="action-link" style="color:var(--accent-green)" @click="moveToProducing(row)">移动</span>
+                <span v-if="row.status === 'online' || row.status === 'ready'"
+                      class="action-link" style="color:var(--accent-green)" @click="openMove(row)">移动</span>
               </td>
             </tr>
             <tr v-if="!tableData.length && !loading">
@@ -239,11 +239,42 @@
         </div>
       </div>
     </div>
+
+    <!-- 移动-位置选择弹窗 -->
+    <div v-if="moveDialog.visible" class="modal-mask" @click.self="moveDialog.visible=false">
+      <div class="modal-box" style="width:480px;">
+        <div class="modal-header">
+          移动计划 — {{ moveDialog.plan && (moveDialog.plan.cold_coil_no || moveDialog.plan.plan_no) }}
+          <span class="modal-close" @click="moveDialog.visible=false">✕</span>
+        </div>
+        <div class="modal-body">
+          <div class="kv-label" style="margin-bottom:8px;">选择目标位置（只有「上卷鞍座」会触发生产）</div>
+          <div class="pos-pick">
+            <span
+              v-for="pos in positions"
+              :key="pos"
+              :class="['pick-item', { active: moveDialog.target === pos, saddle: pos === '上卷鞍座' }]"
+              @click="moveDialog.target = pos"
+            >{{ pos }}</span>
+          </div>
+        </div>
+        <div class="modal-footer">
+          <button class="btn btn-outline" @click="moveDialog.visible=false">取消</button>
+          <button class="btn btn-primary" :disabled="!moveDialog.target || moving" @click="confirmMove">{{ moving ? '移动中...' : '确定' }}</button>
+        </div>
+      </div>
+    </div>
   </div>
 </template>
 
 <script>
-import { getPlans, createPlan, updatePlan, confirmPlan as apiConfirm, startProducing, getLastPlanTemplate } from '@/api'
+import { getPlans, createPlan, updatePlan, confirmPlan as apiConfirm, movePlan, getLastPlanTemplate } from '@/api'
+
+const SADDLE = '上卷鞍座'
+const POSITIONS = [
+  '1#上卷小车', '2#上卷小车', '1#称重位', '2#称重位',
+  '1#地辊', '2#地辊', '1#倒卷小车', '2#倒卷小车', SADDLE,
+]
 
 const STATUS_MAP = {
   ready:     { label: '准备好',   badge: 'badge-gray'   },
@@ -269,6 +300,8 @@ export default {
       dialogVisible: false, editRow: null,
       form: this.emptyForm(),
       selectedRow: null,
+      positions: POSITIONS, moving: false,
+      moveDialog: { visible: false, plan: null, target: '' },
     }
   },
   created() { this.fetchData() },
@@ -348,15 +381,21 @@ export default {
       this.$message.success('已上线')
       this.fetchData()
     },
-    async moveToProducing(row) {
-      if (!confirm(`将计划 ${row.cold_coil_no || row.plan_no} 移动到上卷鞍座？`)) return
+    openMove(row) {
+      this.moveDialog = { visible: true, plan: row, target: row.position || '' }
+    },
+    async confirmMove() {
+      const { plan, target } = this.moveDialog
+      if (!target) return
+      this.moving = true
       try {
-        await startProducing(row.id)
-        this.$message.success('已移动到上卷鞍座')
+        await movePlan(plan.id, target)
+        this.$message.success(target === SADDLE ? '已移动到上卷鞍座' : `已移动到 ${target}`)
+        this.moveDialog.visible = false
         this.fetchData()
       } catch (e) {
         this.$message.error(e?.response?.data?.detail || '操作失败')
-      }
+      } finally { this.moving = false }
     },
     async save() {
       if (!this.form.plan_no) { this.$message.error('计划号不能为空'); return }
@@ -405,4 +444,13 @@ export default {
 .modal-header { display: flex; align-items: center; justify-content: space-between; padding: 12px 16px; background: $bg-panel; border-bottom: 1px solid $border; font-size: 13px; font-weight: 600; color: $sms-highlight; .modal-close { cursor: pointer; color: $text-muted; &:hover { color: $text-primary; } } }
 .modal-body { padding: 16px; overflow-y: auto; }
 .modal-footer { padding: 10px 16px; background: $bg-panel; border-top: 1px solid $border; display: flex; justify-content: flex-end; gap: 10px; }
+.pos-pick { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
+.pick-item {
+  padding: 9px 12px; font-size: 12px; text-align: center; border-radius: 6px; cursor: pointer;
+  border: 1px solid $border; color: $text-secondary; background: $bg-card;
+  &:hover { border-color: $sms-teal; color: $sms-teal; }
+  &.active { color: #fff; background: $sms-teal; border-color: $sms-teal; }
+  &.saddle { grid-column: 1 / -1; border-style: dashed; border-color: $accent-yellow; color: $accent-yellow;
+    &.active { color: #fff; background: $accent-yellow; border-style: solid; } }
+}
 </style>