server : drop the stale monitor thread join in remove()

Assisted-by: pi:llama.cpp/DeepSeek-V4.1-Flash

tools/server/server-models.cpp

@@ -1398,21 +1398,9 @@ bool server_models::remove(const std::string & name) {
         return true;
     }
 
-    // on the cancelled-download path the status flips to DOWNLOADED while the
-    // monitoring thread still has a mutex-guarded step left, so joining under
-    // the lock would deadlock - join outside, as load_models() does
-    std::thread th = std::move(it->second.th);
-    mapping.erase(name);
-    lk.unlock();
-
-    // join first so the monitoring thread's final mutex-guarded cleanup cannot
-    // race the disk removal, then remove from disk without holding the lock
-    // (best-effort: cancelled downloads may have no cached files)
-    if (th.joinable()) {
-        th.join();
-    }
-
+    // remove from disk (best-effort: cancelled downloads may have no cached files)
     bool ok = common_download_remove(name);
+    mapping.erase(name);
 
     if (!ok) {
         SRV_WRN("removing model name=%s from disk returned false (no cached files?)\n", name.c_str());