Method shutdown

server/src/server/http_server.cpp:1042–1088

void HttpServer::broadcast_status() {
    std::string event = status_.to_sse_event();
    std::lock_guard<std::mutex> lk(sse_mu_);
    std::vector<SocketHandle> dead;
    for (SocketHandle fd : sse_fds_) {
        if (!sse_try_send(fd, event.data(), event.size())) {
            dead.push_back(fd);
        }
    }
    for (SocketHandle fd : dead) {
        socket_close(fd);
        sse_fds_.erase(std::remove(sse_fds_.begin(), sse_fds_.end(), fd),
                       sse_fds_.end());
    }
}

// Broadcast a token text delta as an incremental SSE event.
void HttpServer::broadcast_token(const std::string & text) {
    // Token text may contain incomplete UTF-8 (tokens can split multi-byte
    // codepoints). Manually build the SSE payload with json string escaping
    // that replaces invalid UTF-8 with U+FFFD instead of throwing.
    json j;
    j["text"] = text;
    std::string event = "event: token\ndata: " +
        j.dump(-1, ' ', false, json::error_handler_t::replace) + "\n\n";
    std::lock_guard<std::mutex> lk(sse_mu_);
    std::vector<SocketHandle> dead;
    for (SocketHandle fd : sse_fds_) {
        if (!sse_try_send(fd, event.data(), event.size())) {
            dead.push_back(fd);
        }
    }
    for (SocketHandle fd : dead) {
        socket_close(fd);
        sse_fds_.erase(std::remove(sse_fds_.begin(), sse_fds_.end(), fd),
                       sse_fds_.end());
    }
}

// Send an SSE comment as a heartbeat to detect disconnected clients when idle.
// Uses non-blocking sends to avoid stalling the worker thread on slow clients.
void HttpServer::sse_heartbeat() {
    static const char ping[] = ":heartbeat\n\n";
    std::lock_guard<std::mutex> lk(sse_mu_);
    std::vector<SocketHandle> dead;
    for (SocketHandle fd : sse_fds_) {
        // Non-blocking send: if the socket buffer can't accept 12 bytes
        // immediately, the client is too far behind — treat as dead.
        ssize_t n = ::send(fd, ping, sizeof(ping) - 1, MSG_NOSIGNAL | MSG_DONTWAIT);
        if (n <= 0) {
            dead.push_back(fd);
        }