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

docs/INSTALL.md

@@ -0,0 +1,52 @@
+# Installation
+
+## Prerequisites
+
+- Python 3.11+
+- git
+
+## Setup
+
+```bash
+cd ~/git/derp
+make install
+```
+
+This creates a `.venv`, installs derp in editable mode, and adds dev tools.
+
+## Symlink
+
+```bash
+make link
+```
+
+Installs `derp` to `~/.local/bin/`. Verify:
+
+```bash
+which derp
+derp --version
+```
+
+## Manual Install
+
+```bash
+python3 -m venv .venv
+source .venv/bin/activate
+pip install -e .
+```
+
+## Configuration
+
+Copy and edit the default config:
+
+```bash
+cp config/derp.toml ~/.config/derp/derp.toml
+# Edit server, nick, channels
+```
+
+Config search order:
+
+1. Path given via `--config`
+2. `./config/derp.toml`
+3. `~/.config/derp/derp.toml`
+4. Built-in defaults