feat(wxpa): 配图提示词规则从 Go 硬编码迁移到 JSON 配置驱动

- 新增 spec/06-image_prompt_generation/rule.json 定义配图分布规则（500 字间隔、封面图、正文图尺寸）
- 新增 prompt_template、bracket_format 等 JSON 配置，支持中文提示词模板
- 修改 buildCoverImagePrompt/buildContentImagePrompt 使用 strings.ReplaceAll 替换 {index}/{section_summary} 占位符
- 修改 executeWeixinPublicAccountImagePromptStep 调用 buildWeixinPublicAccountImagePromptsV2
- 新增 buildWeixinPublicAccountContentWithPromptsFromJSON 包装 renderWeixinPublicAccountImagePromptFromJSON
- 前端产物 Tab 新增配图缩略图行展示

eai_agentplatform/frontend/src/components/chat/WeixinPublicAccountSpecialistPanel.vue

@@ -148,20 +148,51 @@
               </div>
 
               <div v-else-if="group.kind === 'files'" class="oa-file-list">
-                <div v-for="file in group.files" :key="file.key" class="oa-file-row">
-                  <span class="oa-file-kind">{{ file.kindLabel }}</span>
-                  <div class="oa-file-main">
-                    <span class="oa-file-name" :title="file.name">{{ file.name }}</span>
-                    <span v-if="file.meta" class="oa-file-meta">{{ file.meta }}</span>
+                <div v-if="group.isImageGroup" class="oa-image-group">
+                  <div class="oa-image-group-summary">{{ group.summary }}</div>
+                  <div v-for="file in group.files" :key="file.key" class="oa-image-row">
+                    <img
+                      v-if="file.thumbnailUrl"
+                      :src="file.thumbnailUrl"
+                      :alt="file.name"
+                      class="oa-image-thumb"
+                    />
+                    <img
+                      v-else
+                      src="data:image/svg+xml;charset=utf-8,"
+                      alt="加载中"
+                      class="oa-image-thumb oa-image-thumb-loading"
+                    />
+                    <div class="oa-image-row-info">
+                      <span class="oa-image-row-section">{{ file.meta }}</span>
+                      <span v-if="file.size" class="oa-image-row-size">{{ file.size }}</span>
+                    </div>
+                    <button
+                      class="oa-btn oa-btn-tiny"
+                      type="button"
+                      :disabled="previewLoading"
+                      @click="downloadFile(file)"
+                    >
+                      下载
+                    </button>
+                  </div>
+                </div>
+                <div v-else class="oa-file-list-plain">
+                  <div v-for="file in group.files" :key="file.key" class="oa-file-row">
+                    <span class="oa-file-kind">{{ file.kindLabel }}</span>
+                    <div class="oa-file-main">
+                      <span class="oa-file-name" :title="file.name">{{ file.name }}</span>
+                      <span v-if="file.meta" class="oa-file-meta">{{ file.meta }}</span>
+                    </div>
+                    <button
+                      class="oa-btn oa-btn-tiny"
+                      type="button"
+                      :disabled="previewLoading"
+                      @click="downloadFile(file)"
+                    >
+                      下载
+                    </button>
                   </div>
-                  <button
-                    class="oa-btn oa-btn-tiny"
-                    type="button"
-                    :disabled="previewLoading"
-                    @click="downloadFile(file)"
-                  >
-                    下载
-                  </button>
                 </div>
               </div>
 
@@ -695,10 +726,49 @@ const artifactStepGroups = computed(() => orderedSteps.value.map((step, index) =
   }
 }))
 const artifactItems = computed(() => artifactStepGroups.value.map((group) => group.artifact).filter(Boolean))
-// 一份产物都没有时不再列 8 个「这一步还没有产物」的空壳，只留一句提示。
-// 跑过几步的任务则八步全列，缺哪一步一眼能看出来。
-const visibleArtifactGroups = computed(() => (artifactItems.value.length ? artifactStepGroups.value : []))
+const visibleArtifactGroups = computed(() => (artifactItems.value.length ? artifactStepGroupsWithThumbnails.value : []))
 const previewTitle = computed(() => (previewTarget.value?.name ? `预览 · ${previewTarget.value.name}` : '预览'))
+const artifactImageUrls = computed(() => {
+  // Collect all image URLs from artifact files so we can load thumbnails
+  const urls = []
+  artifactStepGroups.value.forEach((group) => {
+    if (group.isImageGroup && group.files) {
+      group.files.forEach((file) => {
+        if (file.url) urls.push(String(file.url))
+      })
+    }
+  })
+  return urls
+})
+const artifactImageObjectUrls = computed(() => {
+  const result = {}
+  artifactImageUrls.value.forEach((url) => {
+    result[url] = imageObjectUrls.value[url] || ''
+  })
+  return result
+})
+
+// Augment artifact step groups with thumbnail URLs
+const artifactStepGroupsWithThumbnails = computed(() => {
+  return artifactStepGroups.value.map((group) => {
+    if (group.isImageGroup && group.files) {
+      return {
+        ...group,
+        files: group.files.map((file) => {
+          if (file.kind === 'image' && file.url) {
+            return {
+              ...file,
+              thumbnailUrl: artifactImageObjectUrls.value[String(file.url)] || imageObjectUrls.value[String(file.url)] || '',
+            }
+          }
+          return file
+        }),
+      }
+    }
+    return group
+  })
+})
+
 const uploadItems = computed(() => {
   const rawList = collectUploadItems(parseTaskContext(workflowTask.value))
   return rawList.map((item, index) => normalizeUploadItem(item, index)).filter(Boolean)
@@ -1335,10 +1405,17 @@ function buildArtifactView(item, stepKey) {
   }
 
   if (base.kind === 'files') {
-    const files = buildArtifactFiles(payload, view.type)
-    if (!files.length) return degradeArtifactView(base, stepKey)
-    base.files = files
-    base.summary = artifactFilesSummary(files, payload, view.type)
+    const filesOrGroup = buildArtifactFiles(payload, view.type)
+    if (!filesOrGroup || (Array.isArray(filesOrGroup) && !filesOrGroup.length)) return degradeArtifactView(base, stepKey)
+    // images 返回的是 { isImageGroup: true, summary, files } 对象
+    if (filesOrGroup.isImageGroup) {
+      base.isImageGroup = true
+      base.summary = filesOrGroup.summary
+      base.files = filesOrGroup.files
+    } else {
+      base.files = filesOrGroup
+      base.summary = artifactFilesSummary(filesOrGroup, payload, view.type)
+    }
     base.body = ''
     return base
   }
@@ -1444,17 +1521,22 @@ function artifactRowsSummary(payload, artifactType, rows) {
 function buildArtifactFiles(payload, artifactType) {
   if (artifactType === 'images') {
     const refs = Array.isArray(payload?.image_refs) ? payload.image_refs : []
-    return refs.map((ref, idx) => {
-      const url = String(ref?.url || '').trim()
-      return {
-        key: `image-${ref?.key || idx}`,
-        kind: 'image',
-        kindLabel: '图片',
-        name: fileNameOfUrl(url) || `生成图 ${idx + 1}.png`,
-        meta: String(ref?.section || ref?.key || '').trim(),
-        url,
-      }
-    }).filter((file) => file.url)
+    return {
+      isImageGroup: true,
+      summary: `计划生成 ${refs.length} 张配图`,
+      files: refs.map((ref, idx) => {
+        const url = String(ref?.url || '').trim()
+        return {
+          key: `image-${ref?.key || idx}`,
+          kind: 'image',
+          kindLabel: '图片',
+          name: fileNameOfUrl(url) || `生成图 ${idx + 1}.png`,
+          meta: String(ref?.section || ref?.key || '').trim(),
+          size: ref?.image_size ? sizeLabel(ref.image_size) : '',
+          url,
+        }
+      }).filter((file) => file.url),
+    }
   }
   if (artifactType === 'preview') {
     const html = String(payload?.preview_html || '').trim()
@@ -1551,12 +1633,31 @@ function formatFileSize(value) {
   return `${(size / (1024 * 1024)).toFixed(1)} MB`
 }
 
+// 图片尺寸标签
+function sizeLabel(imageSize) {
+  const map = {
+    'landscape_16_9': '16:9 横图',
+    'landscape_4_3': '4:3 横图',
+    'portrait_4_3': '4:3 竖图',
+    'square_hd': '1:1 方形',
+  }
+  return map[imageSize] || imageSize
+}
+
 watch(
   () => [currentSpecialistKey.value, currentTaskId.value],
   refresh,
   { immediate: true }
 )
 
+watch(
+  artifactImageUrls,
+  (urls) => {
+    urls.forEach((url) => ensureImageObjectUrl(url))
+  },
+  { immediate: true, deep: true }
+)
+
 watch(
   imageRefs,
   (list) => {
@@ -2088,6 +2189,67 @@ onBeforeUnmount(() => {
   margin-top: 4px;
 }
 
+/* 产物 Tab 中图片生成步骤的缩略图行 */
+.oa-image-group-summary {
+  font-size: 12px;
+  color: #8c8c8c;
+  margin-bottom: 8px;
+  font-weight: 500;
+}
+
+.oa-image-row {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  padding: 6px 0;
+  border-bottom: 1px solid #f0f0f0;
+}
+
+.oa-image-row:last-child {
+  border-bottom: none;
+}
+
+.oa-image-thumb {
+  width: 48px;
+  height: 36px;
+  object-fit: cover;
+  border-radius: 4px;
+  flex-shrink: 0;
+  background: #f5f5f5;
+}
+
+.oa-image-thumb-loading {
+  opacity: 0;
+  transition: opacity 0.2s;
+}
+
+.oa-image-row-info {
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+  min-width: 0;
+  flex: 1;
+}
+
+.oa-image-row-section {
+  font-size: 13px;
+  color: #333;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.oa-image-row-size {
+  font-size: 11px;
+  color: #999;
+}
+
+.oa-file-list-plain {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+}
+
 .oa-image-list {
   display: grid;
   grid-template-columns: repeat(2, minmax(0, 1fr));