feat(jm): 新增 JM 漫画下载打包服务（9004，移植自 qqbot jm 模块）

- source/jm/jm.py：aiohttp + jmcomic，GET /jm/get_comic?id=xxx[&range=起-止]
  下载至 cache/jm 隐藏暂存目录 → webp 转 jpg 打包 ZIP → HTTP 直返 → 600s 延时删除
  单次上限 30 章；per-album 锁防并发；cache_sweep 兜底清理；/jm/cache_info 运维接口
- source/main.py：聚合层注册 /jm/get_comic（新增 JM_BACKEND，复用 proxy()）
- systemd/jm.service：独立系统服务（Restart=always，日志 /var/log/jm.log）
- README / 部署与运维文档同步更新

source/main.py

@@ -4,6 +4,7 @@ from aiohttp import web, ClientSession, ClientTimeout
 PIXIV_BACKEND = "http://127.0.0.1:9007"
 BILIBILI_BACKEND = "http://127.0.0.1:9006"
 DUFE_BACKEND = "http://127.0.0.1:9005"
+JM_BACKEND = "http://127.0.0.1:9004"
 
 
 async def handle_pixiv(request):
@@ -30,6 +31,14 @@ async def handle_dufe_sign_in(request):
     return await proxy_forward(request, target)
 
 
+async def handle_jm(request):
+    qs = request.query_string
+    target = f"{JM_BACKEND}/jm/get_comic"
+    if qs:
+        target += "?" + qs
+    return await proxy(request, target)
+
+
 async def proxy(request, target):
     timeout = ClientTimeout(total=300)
     async with ClientSession(timeout=timeout) as session:
@@ -92,6 +101,7 @@ app.router.add_get("/pixiv/get_image", handle_pixiv)
 app.router.add_get("/bilibili/get_video", handle_bilibili)
 app.router.add_get("/dufe/ginkgostu_sign_in", handle_dufe_sign_in)
 app.router.add_post("/dufe/ginkgostu_sign_in", handle_dufe_sign_in)
+app.router.add_get("/jm/get_comic", handle_jm)
 
 if __name__ == "__main__":
     web.run_app(app, host="127.0.0.1", port=9008)