修复自动化任务：bot-activity上线 + task7板块slug修复 + cron强化

问题排查与修复：
1. 🔴 bot-activity从未运行 — 新增cron任务（9-23点每小时15轮）
2. 🔴 task7报错'板块不存在: ai-tools' — 更新所有slug为新的51子板块格式
3. 🟡 install-cron.sh旧cron清理不完整 — 改为覆盖模式
4. 🟡 Google News RSS被墙 — 优化fallback提示词用DeepSeek知识+当前日期

效果：
- 8个定时任务全部正常运行
- 首次运行产出10个话题(7+3)，社区从12→24帖
- 每小时15轮持续产出，预计每天~45帖

scripts/task7-news-to-community.mjs

@@ -27,18 +27,18 @@ function ensureUniqueSlug(title) {
 }
 
 const CATEGORY_MAP = {
-  "产品发布": "ai-tools",
-  "product": "ai-tools",
-  "融资投资": "ai-news",
-  "business": "ai-news",
-  "技术突破": "tech",
-  "model": "tech",
-  "政策法规": "ai-news",
-  "policy": "ai-news",
-  "开源项目": "tech",
-  "opensource": "tech",
-  "行业事件": "ai-news",
-  "insight": "discuss",
+  "产品发布": "ai-tools-app",
+  "product": "ai-tools-app",
+  "融资投资": "ai-startup-forum",
+  "business": "ai-startup-forum",
+  "技术突破": "ai-llm",
+  "model": "ai-llm",
+  "政策法规": "ai-startup-forum",
+  "policy": "ai-startup-forum",
+  "开源项目": "ai-llm",
+  "opensource": "ai-llm",
+  "行业事件": "ai-startup-forum",
+  "insight": "ai-startup-forum",
 };
 
 async function main() {
@@ -89,7 +89,7 @@ async function main() {
 
   const forumCategories = await prisma.forumCategory.findMany({
     where: {
-      slug: { in: ["ai-tools", "ai-news", "tech", "discuss"] },
+      slug: { in: ["ai-tools-app", "ai-startup-forum", "ai-llm"] },
     },
   });
   const categoryBySlug = {};
@@ -98,7 +98,7 @@ async function main() {
   }
   console.log(`${ts()} 📂 已加载${forumCategories.length}个社区板块: ${Object.keys(categoryBySlug).join(", ")}`);
 
-  const requiredSlugs = ["ai-tools", "ai-news", "tech", "discuss"];
+  const requiredSlugs = ["ai-tools-app", "ai-startup-forum", "ai-llm"];
   for (const slug of requiredSlugs) {
     if (!categoryBySlug[slug]) {
       throw new Error(`社区板块不存在: ${slug}，请先在管理后台创建社区分类`);