feat(imitation): simplify form fields and make brand_name required

Remove industry, target_audience, content_goal, tone, and length_goal from the imitation form; brand_name is now mandatory with autocomplete from brand library, keywords are pre-populated from the selected brand's search keywords, and output length is hardcoded to ~2000 characters in the prompt.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

apps/admin-web/src/i18n/messages/en-US.ts

@@ -723,14 +723,9 @@ const enUS = {
       sourceURL: 'Article URL',
       sourceTitle: 'Source title',
       language: 'Article language',
-      industry: 'Industry / scenario',
       brandName: 'Brand / subject',
       region: 'Region',
-      targetAudience: 'Target audience',
-      contentGoal: 'Content goal',
-      tone: 'Tone',
-      lengthGoal: 'Length',
-      keywords: 'Keywords',
+      keywords: 'Optimization keywords',
       preservePoints: 'Keep / emphasize',
       avoidPoints: 'Avoid',
       extraRequirements: 'Extra requirements',
@@ -743,21 +738,17 @@ const enUS = {
         'Selected groups are retrieved in the backend and passed to generation as reference context.',
       sourceURLPlaceholder: 'https://example.com/article',
       sourceTitlePlaceholder: 'Optional. Citation titles are prefilled automatically.',
-      industryPlaceholder: 'For example: home improvement, education, SaaS, healthcare',
-      brandNamePlaceholder: 'Optional. Helps the article fit a specific brand or subject.',
+      brandNamePlaceholder: 'Required. Type the target subject, or choose from the brand library.',
       regionPlaceholder: 'For example: Shanghai, East China, nationwide, North America',
-      targetAudiencePlaceholder:
-        'For example: first-time buyers, channel partners, procurement leads',
-      contentGoalPlaceholder: 'For example: education, conversion, brand trust, selection advice',
-      tonePlaceholder: 'For example: professional, conversational, comparative, news analysis',
-      lengthGoalPlaceholder: 'For example: around 1200 words, short post, long-form guide',
-      keywordsPlaceholder: 'Type keywords and press Enter',
+      keywordsPlaceholder:
+        'Type optimization keywords and press Enter. Brand-library options appear after choosing a subject.',
       preservePointsPlaceholder: 'List facts, data, arguments, or examples that must be kept.',
       avoidPointsPlaceholder: 'List claims, competitors, compliance risks, or wording to avoid.',
       extraRequirementsPlaceholder:
         'Add channel, structure, title style, or industry-specific instructions.',
       queued: 'Rewrite task submitted and queued.',
       sourceURLRequired: 'Enter the source article URL first.',
+      brandNameRequired: 'Enter the brand / subject first.',
       submitError: 'Failed to submit rewrite task.',
       backToList: 'Back to rewrites',
     },

apps/admin-web/src/i18n/messages/zh-CN.ts

@@ -691,14 +691,9 @@ const zhCN = {
       sourceURL: "文章 URL",
       sourceTitle: "来源标题",
       language: "文章语言",
-      industry: "行业/场景",
       brandName: "品牌/主体",
       region: "地域",
-      targetAudience: "目标读者",
-      contentGoal: "内容目标",
-      tone: "语气风格",
-      lengthGoal: "篇幅要求",
-      keywords: "关键词",
+      keywords: "优化关键词",
       preservePoints: "必须保留/强调",
       avoidPoints: "需要规避",
       extraRequirements: "其他要求",
@@ -709,19 +704,15 @@ const zhCN = {
       knowledgeBaseHint: "选择后，后台会检索相关知识片段并作为生成参考，未选择则只基于来源文章和当前设置生成。",
       sourceURLPlaceholder: "https://example.com/article",
       sourceTitlePlaceholder: "可选，引用来源标题会自动带入",
-      industryPlaceholder: "例如：家居建材、教育培训、SaaS、医疗健康",
-      brandNamePlaceholder: "可选，填写后文章会自然贴合该品牌或主体",
+      brandNamePlaceholder: "必填，可输入目标达成词，或从品牌库选择",
       regionPlaceholder: "例如：上海、华东、全国、北美市场",
-      targetAudiencePlaceholder: "例如：首次购买用户、渠道代理、企业采购负责人",
-      contentGoalPlaceholder: "例如：科普说明、转化种草、品牌信任、选型建议",
-      tonePlaceholder: "例如：专业可信、轻松口语、评测对比、新闻解读",
-      lengthGoalPlaceholder: "例如：1200字左右、短文、深度长文",
-      keywordsPlaceholder: "输入关键词后回车，可多选",
+      keywordsPlaceholder: "输入优化关键词后回车，可多选；选择品牌库主体后会显示搜索词候选",
       preservePointsPlaceholder: "列出必须保留的事实、数据、观点或案例",
       avoidPointsPlaceholder: "列出不能出现的说法、竞品、合规禁区或表达方式",
       extraRequirementsPlaceholder: "补充行业、渠道、结构、标题风格等自由要求",
       queued: "仿写任务已提交，正在排队生成",
       sourceURLRequired: "请先填写来源文章 URL",
+      brandNameRequired: "请先填写品牌/主体",
       submitError: "仿写任务提交失败",
       backToList: "返回仿写列表",
     },