chore: sync plugin from AstrBotDevs/AstrBot#6663

Author: astrbot-plugin-copybara[bot]

plugins.json

@@ -1,4 +1,15 @@
 {
+  "astrbot-plugin-arxiv": {
+    "display_name": "ArXiv Paper Pusher",
+    "desc": "ArXiv 论文搜索与定时推送，支持 LLM 摘要翻译、PDF 处理、合并转发等。",
+    "author": "NayukiChiba",
+    "repo": "https://github.com/NayukiChiba/astrbot_plugin_arxiv",
+    "tags": [
+      "论文",
+      "定时"
+    ],
+    "social_link": "https://github.com/NayukiChiba"
+  },
   "astrbot-plugin-cve-warning": {
     "display_name": "CVE漏洞推送",
     "desc": "基于 CISA KEV（Known Exploited Vulnerabilities）定时推送，并按 CVSS 严重等级对消息进行分级展示。",