feat: initial implementation

Asyncio IRC bot with decorator-based plugin system.
Zero external dependencies, Python 3.11+.

- IRC protocol: message parsing, formatting, async TCP/TLS connection
- Plugin system: @command and @event decorators, file-based loading
- Bot orchestrator: connect, dispatch, reconnect, nick recovery
- CLI: argparse entry point with TOML config
- Built-in plugins: ping, help, version, echo
- 28 unit tests for parser and plugin system

plugins/core.py

@@ -0,0 +1,39 @@
+"""Core plugin: ping, help, version."""
+
+from derp import __version__
+from derp.plugin import command
+
+
+@command("ping", help="Check if the bot is alive")
+async def cmd_ping(bot, message):
+    """Respond with pong."""
+    await bot.reply(message, "pong")
+
+
+@command("help", help="List commands or show command help")
+async def cmd_help(bot, message):
+    """Show available commands or help for a specific command.
+
+    Usage: !help [command]
+    """
+    parts = message.text.split(None, 2)
+    if len(parts) > 1:
+        # Help for a specific command
+        cmd_name = parts[1].lower().lstrip(bot.prefix)
+        handler = bot.registry.commands.get(cmd_name)
+        if handler:
+            help_text = handler.help or "No help available."
+            await bot.reply(message, f"{bot.prefix}{cmd_name} -- {help_text}")
+        else:
+            await bot.reply(message, f"Unknown command: {cmd_name}")
+        return
+
+    # List all commands
+    names = sorted(bot.registry.commands.keys())
+    await bot.reply(message, f"Commands: {', '.join(bot.prefix + n for n in names)}")
+
+
+@command("version", help="Show bot version")
+async def cmd_version(bot, message):
+    """Report the running version."""
+    await bot.reply(message, f"derp {__version__}")