M1 step 5: IRC App

- Chat: header (Buffer n/N, unread elsewhere, topic or connection
  state), wrapped hh:mm <nick> lines (own in accent, Mentions green,
  info grey), input line; Tab cycles Buffers, Fn+Up/Down scrolls back,
  Enter sends, Back leaves while the IRC Service keeps running
- /settings: server form (host, port, TLS, self-signed pinning, nick,
  SASL, NickServ, auto-join); Save & reconnect restarts the session
- Opening the App starts the IRC Service; viewing a Buffer clears its
  unread count; IrcSession gains a revision counter for redraws

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/services/irc_service.h

@@ -45,7 +45,7 @@ class IrcService : public Service {
     int totalUnread();
 
     IrcConfig& config() { return config_; }
-    // Saves the config; takes effect at the next connection.
+    // Saves the config and, if running, reconnects with it (a fresh session).
     std::string saveConfig();
 
    private:
@@ -77,6 +77,7 @@ class IrcService : public Service {
     ReconnectPolicy backoff_;
     std::string partial_;
     volatile bool wanted_ = false;
+    volatile bool restart_ = false;
     volatile Status status_ = Status::Stopped;
     bool open_ = false;
     uint32_t retryAtMs_ = 0;