feat(backend): implement task creation and admin web

docs/design/admin-task-create.html

@@ -210,6 +210,12 @@
               <input id="title" name="title" maxlength="120" placeholder="例如：演示用桌面收纳盒">
               <p id="title-error" class="error"></p>
             </div>
+            <div class="span-2">
+              <label class="required" for="sku">SKU</label>
+              <input id="sku" name="sku" maxlength="120" placeholder="例如：浅灰色 · 中号">
+              <p id="sku-error" class="error"></p>
+              <p class="help">SKU 是不可覆盖的原始采购要求。</p>
+            </div>
             <div class="span-2">
               <label for="description">商品描述</label>
               <textarea id="description" name="description" placeholder="填写规格、颜色、材质等判断条件"></textarea>
@@ -221,7 +227,7 @@
               <p id="quantity-error" class="error"></p>
             </div>
             <div>
-              <label for="budget">最高总预算（元）</label>
+              <label for="budget">最高商品总预算（元）</label>
               <input id="budget" name="budget" type="number" min="0.01" step="0.01" inputmode="decimal" placeholder="不填写则不设上限">
               <p id="budget-error" class="error"></p>
             </div>
@@ -284,7 +290,7 @@
     });
 
     function clearFeedback() {
-      ['title', 'quantity', 'budget', 'image'].forEach((name) => {
+      ['title', 'sku', 'quantity', 'budget', 'image'].forEach((name) => {
         document.querySelector(`#${name}-error`).textContent = '';
       });
       notice.style.display = 'none';
@@ -303,18 +309,23 @@
       clearFeedback();
       let firstInvalid = null;
       const title = document.querySelector('#title');
+      const sku = document.querySelector('#sku');
       const quantity = document.querySelector('#quantity');
       const budget = document.querySelector('#budget');
       if (!title.value.trim()) {
         document.querySelector('#title-error').textContent = '请输入商品标题。';
         firstInvalid ||= title;
       }
+      if (!sku.value.trim()) {
+        document.querySelector('#sku-error').textContent = '请输入 SKU。';
+        firstInvalid ||= sku;
+      }
       if (!Number.isInteger(Number(quantity.value)) || Number(quantity.value) < 1) {
         document.querySelector('#quantity-error').textContent = '数量必须是大于 0 的整数。';
         firstInvalid ||= quantity;
       }
       if (budget.value && Number(budget.value) <= 0) {
-        document.querySelector('#budget-error').textContent = '预算必须大于 0，或留空。';
+        document.querySelector('#budget-error').textContent = '商品总预算必须大于 0，或留空。';
         firstInvalid ||= budget;
       }
       if (!image.files.length) {

docs/design/admin-task-detail.html

@@ -289,8 +289,9 @@
                   <p class="description">桌面用分格收纳盒，浅灰色，塑料材质。
 需要带可拆分隔板，外观接近参考图。</p>
                   <div class="constraints">
+                    <span class="constraint">SKU：浅灰色 · 中号</span>
                     <span class="constraint">数量：2</span>
-                    <span class="constraint">最高总预算：60.00 元</span>
+                    <span class="constraint">最高商品总预算：60.00 元</span>
                     <span class="constraint">关键属性：浅灰 / 分隔板</span>
                   </div>
                 </div>

docs/design/android-candidate-confirm.html

@@ -38,14 +38,14 @@
       </section>
       <section class="panel" id="requirement" aria-labelledby="requirementTitle">
         <h2 id="requirementTitle">管理员原始要求</h2>
-        <dl class="facts"><dt>商品</dt><dd>透明抽屉式收纳盒</dd><dt>SKU</dt><dd>白色 · 中号</dd><dt>数量</dt><dd>2 件</dd><dt>最高预算</dt><dd>¥ 48.00 / 件</dd></dl>
+        <dl class="facts"><dt>商品</dt><dd>透明抽屉式收纳盒</dd><dt>SKU</dt><dd>白色 · 中号</dd><dt>数量</dt><dd>2 件</dd><dt>最高商品总预算</dt><dd>¥ 96.00</dd></dl>
       </section>
       <section class="panel" id="candidate" aria-labelledby="candidateTitle">
         <h2 id="candidateTitle">候选 1 / 3</h2>
         <div class="evidence" role="img" aria-label="脱敏的候选商品截图占位">脱敏候选截图<br>证据占位</div>
         <dl class="facts"><dt>候选标题</dt><dd>透明可叠放抽屉收纳盒</dd><dt>单价</dt><dd class="price" id="price">¥ 39.90</dd></dl>
         <h3>匹配与风险</h3>
-        <ul class="checks" id="checks"><li><span class="ok">符合</span> 颜色：白色</li><li><span class="ok">符合</span> 规格：中号</li><li><span class="ok">符合</span> 单价未超过预算</li></ul>
+        <ul class="checks" id="checks"><li><span class="ok">符合</span> 颜色：白色</li><li><span class="ok">符合</span> 规格：中号</li><li><span class="ok">符合</span> 商品总价 ¥ 79.80 未超过预算</li></ul>
       </section>
       <section class="panel">
         <h2>人员结论</h2>
@@ -65,7 +65,7 @@
   </dialog>
   <script>
     const scenario=document.querySelector("#scenario"),candidate=document.querySelector("#candidate"),accept=document.querySelector("#accept"),reject=document.querySelector("#reject"),noneAction=document.querySelector("#noneAction"),price=document.querySelector("#price"),checks=document.querySelector("#checks"),dialog=document.querySelector("#confirmDialog"),cancel=document.querySelector("#cancel"),completion=document.querySelector("#completion");let pending="";
-    function render(){const v=scenario.value,missing=v==="none";candidate.hidden=missing;noneAction.disabled=!missing;accept.disabled=v!=="valid";reject.disabled=missing;if(v==="over"){price.textContent="¥ 56.00";checks.innerHTML='<li><span class="ok">符合</span> 颜色：白色</li><li><span class="ok">符合</span> 规格：中号</li><li><span class="risk">不符合</span> 单价超过最高预算，不能接受</li>'}else if(v==="unknown"){price.textContent="¥ 41.00";checks.innerHTML='<li><span class="ok">符合</span> 颜色：白色</li><li><span class="risk">未知</span> 规格无法确认，不能接受</li><li><span class="ok">符合</span> 单价未超过预算</li>'}else{price.textContent="¥ 39.90";checks.innerHTML='<li><span class="ok">符合</span> 颜色：白色</li><li><span class="ok">符合</span> 规格：中号</li><li><span class="ok">符合</span> 单价未超过预算</li>'}}
+    function render(){const v=scenario.value,missing=v==="none";candidate.hidden=missing;noneAction.disabled=!missing;accept.disabled=v!=="valid";reject.disabled=missing;if(v==="over"){price.textContent="¥ 56.00";checks.innerHTML='<li><span class="ok">符合</span> 颜色：白色</li><li><span class="ok">符合</span> 规格：中号</li><li><span class="risk">不符合</span> 商品总价 ¥ 112.00 超过总预算，不能接受</li>'}else if(v==="unknown"){price.textContent="¥ 41.00";checks.innerHTML='<li><span class="ok">符合</span> 颜色：白色</li><li><span class="risk">未知</span> 规格无法确认，不能接受</li><li><span class="ok">符合</span> 商品总价 ¥ 82.00 未超过总预算</li>'}else{price.textContent="¥ 39.90";checks.innerHTML='<li><span class="ok">符合</span> 颜色：白色</li><li><span class="ok">符合</span> 规格：中号</li><li><span class="ok">符合</span> 商品总价 ¥ 79.80 未超过总预算</li>'}}
     document.querySelectorAll("[data-action]").forEach(button=>button.addEventListener("click",()=>{pending=button.dataset.action;document.querySelector("#dialogText").textContent="选择："+pending;dialog.showModal();setTimeout(()=>cancel.focus(),0)}));
     scenario.addEventListener("change",render);cancel.addEventListener("click",()=>dialog.close());dialog.addEventListener("cancel",e=>{e.preventDefault();dialog.close()});document.querySelector("#confirm").addEventListener("click",()=>{dialog.close();completion.classList.add("show");document.querySelector("#completionText").textContent="“"+pending+"”已记录，结果正在同步。";completion.scrollIntoView({behavior:"smooth",block:"start"})});render();
   </script>

docs/design/android-task-preview.html

@@ -31,13 +31,13 @@
           <dt>商品标题</dt><dd>透明抽屉式桌面收纳盒</dd>
           <dt>SKU</dt><dd>白色 · 中号</dd>
           <dt>数量</dt><dd class="constraint">2 件</dd>
-          <dt>最高预算</dt><dd class="constraint">¥ 48.00 / 件</dd>
+          <dt>最高商品总预算</dt><dd class="constraint">¥ 96.00</dd>
           <dt>描述</dt><dd>带把手，可叠放，优先选择相同外观。</dd>
         </dl>
       </section>
       <section class="panel derived" aria-labelledby="derivedTitle">
         <h2 id="derivedTitle">AI 辅助理解 · 待验证</h2>
-        <p>可能关键词：透明、抽屉式、中号、可叠放。最终数量和预算始终以原始要求为准。</p>
+        <p>可能关键词：透明、抽屉式、中号、可叠放。最终 SKU、数量和商品总预算始终以原始要求为准。</p>
       </section>
       <section class="panel">
         <label for="scenario">原型状态</label>