feat(channels): add IRC channel integration

Add IRC as a new channel for picoclaw, supporting server connections,
channel joins, DMs, mention-based group triggers, and IRCv3 typing
indicators. Uses ergochat/irc-go for connection management with SASL,
NickServ, and automatic reconnection support.

Closes #1137

scripts/test-irc.sh

@@ -0,0 +1,56 @@
+#!/bin/sh
+# Starts a local Ergo IRC server for testing the IRC channel.
+#
+# Requirements: docker
+# Usage: ./scripts/test-irc.sh
+
+set -e
+
+CONTAINER_NAME="picoclaw-test-ergo"
+IRC_PORT=6667
+
+# Clean up any previous instance
+docker rm -f "$CONTAINER_NAME" >/dev/null 2>&1 || true
+
+echo "Starting Ergo IRC server on port $IRC_PORT..."
+docker run -d \
+    --name "$CONTAINER_NAME" \
+    -p "$IRC_PORT:6667" \
+    ghcr.io/ergochat/ergo:stable
+
+for i in $(seq 1 10); do
+    if nc -z localhost "$IRC_PORT" 2>/dev/null; then
+        break
+    fi
+    if [ "$i" -eq 10 ]; then
+        echo "ERROR: Server did not start within 10s"
+        exit 1
+    fi
+    sleep 1
+done
+
+echo ""
+echo "IRC server ready on localhost:$IRC_PORT"
+echo ""
+echo "Add this to your ~/.picoclaw/config.json under \"channels\":"
+echo ""
+echo '  "irc": {'
+echo '    "enabled": true,'
+echo '    "server": "localhost:6667",'
+echo '    "tls": false,'
+echo '    "nick": "picobot",'
+echo '    "channels": ["#test"],'
+echo '    "allow_from": [],'
+echo '    "group_trigger": { "mention_only": true }'
+echo '  }'
+echo ""
+echo "Then run picoclaw:"
+echo "  cd packages/picoclaw && go run ./cmd/picoclaw gateway"
+echo ""
+echo "Connect with an IRC client:"
+echo "  irssi:   /connect localhost $IRC_PORT"
+echo "  weechat: /server add test localhost/$IRC_PORT && /connect test"
+echo "  Join #test, then: picobot: hello"
+echo ""
+echo "To stop the IRC server:"
+echo "  docker rm -f $CONTAINER_NAME"