Scaffold the federated services daemon

Protocol-agnostic core: a Protocol trait maps raw server-to-server lines to a
normalized event/action model, so the engine never touches a raw line and a new
ircd is one new module. Adds event-log state (state is a fold over the log) and
a service framework. First protocol impl links to an InspIRCd (insp4) uplink —
completes the CAPAB/SERVER handshake, bursts, and introduces NickServ.

src/config.rs

@@ -0,0 +1,34 @@
+use serde::Deserialize;
+
+#[derive(Debug, Deserialize)]
+pub struct Config {
+    pub uplink: Uplink,
+    pub server: Server,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct Uplink {
+    pub host: String,
+    pub port: u16,
+    pub password: String,
+}
+
+#[derive(Debug, Deserialize)]
+pub struct Server {
+    pub name: String,
+    pub sid: String,
+    pub description: String,
+    #[serde(default = "default_protocol")]
+    pub protocol: u32,
+}
+
+fn default_protocol() -> u32 {
+    1206 // InspIRCd 4 spanning-tree protocol (1205 = insp3)
+}
+
+impl Config {
+    pub fn load(path: &str) -> anyhow::Result<Self> {
+        let raw = std::fs::read_to_string(path)?;
+        Ok(toml::from_str(&raw)?)
+    }
+}