M1 step 4b: IRC Service on the device; 8-bit frame buffer

- IrcService: networking on its own task, TLS with the built-in CA
  bundle (or trust-on-first-use pinning when self-signed is allowed),
  plain TCP when TLS is off; connects only while Wi-Fi is Connected,
  marks pauses for Monitoring, reconnects with backoff, pings a quiet
  server, writes Logs, raises Notifications for Mentions
- Session: forget /quit once disconnected (it was handled every loop);
  the server Buffer never counts as unread (MOTD showed as [4])
- Status Bar: unread count
- Frame buffer 16 -> 8-bit colour (M1 Q46): min free heap with IRC on
  TLS went from 51 KB to 79 KB
- Serial: irc start / say / dump

Verified on the device against irc.libera.chat:6697: certificate
checked, joined #roro9stack-test, sent a message, quit cleanly.

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

lib/irc/src/irc_session.cpp

@@ -93,7 +93,7 @@ void IrcSession::add(int b, IrcLine::Kind kind, const std::string& nick, const s
     effects_.logs.push_back({buf.name, line});
 
     bool fromOthers = kind == IrcLine::Kind::Message || kind == IrcLine::Kind::Action || kind == IrcLine::Kind::Notice;
-    if (b != viewing_ && fromOthers) {
+    if (b != viewing_ && fromOthers && buf.type != IrcBuffer::Type::Server) {
         buf.unread++;
         if (mention) {
             buf.mentioned = true;
@@ -114,6 +114,7 @@ void IrcSession::connected(int64_t) {
 
 void IrcSession::disconnected(int64_t utc, const std::string& reason) {
     registered_ = false;
+    quit_ = false;
     rejoin_.clear();
     for (int i = 0; i < bufferCount(); i++) {
         if (buffers_[i].type == IrcBuffer::Type::Channel && buffers_[i].joined) rejoin_.push_back(buffers_[i].name);