docs: condense implementation comments

server/src/server.cpp

@@ -169,12 +169,8 @@ int Server::run() {
     });
 
     // ── Keepalive reaper (docs/protocol.md §7) ─────────────────────────────────
-    // Sweeps every reaper_sweep_ms and drops any session whose last_seen is older than
-    // reaper_timeout_ms. Each close() broadcasts UserEvent::LEFT via the Tier 1 fix, so
-    // peers learn about the timeout exactly like a normal disconnect — their audio engines
-    // call remove_stream and stop PLC. This catches half-open connections (NAT timeout,
-    // wifi loss without RST, laptop sleep) that never produce a TCP EOF and would otherwise
-    // leave ghost users forever. Disabled when reaper_timeout_ms <= 0.
+    // Drops half-open sessions and broadcasts LEFT so peers remove their streams.
+    // Disabled when reaper_timeout_ms <= 0.
     asio::steady_timer reaper_timer(io);
     std::function<void()> arm_reaper;
     if (cfg_.reaper_timeout_ms > 0) {