modules: split services and the ircd link into external crates

nickserv, chanserv and the InspIRCd protocol move out of the binary into their
own workspace crates (fedserv-nickserv, fedserv-chanserv, fedserv-inspircd),
each depending only on fedserv-api. human_time and the branded account emails
move into the SDK crate so a module needs nothing from core; the engine keeps
its own inherent methods and builds emails via fedserv-api too. The bin now
constructs each module from its crate instead of an in-tree #[path] include.
Proves the SDK is self-sufficient: a third-party module is the same shape.

chanserv/src/kick.rs

@@ -0,0 +1,20 @@
+use fedserv_api::Store;
+use fedserv_api::{Sender, ServiceCtx};
+use fedserv_api::NetView;
+
+// KICK <#channel> <nick> [reason]: kick a user.
+pub fn handle(me: &str, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, net: &dyn NetView, db: &dyn Store) {
+    let (Some(&chan), Some(&nick)) = (args.get(1), args.get(2)) else {
+        ctx.notice(me, from.uid, "Syntax: KICK <#channel> <nick> [reason]");
+        return;
+    };
+    if !super::require_op(me, from, chan, ctx, db) {
+        return;
+    }
+    let Some(target) = net.uid_by_nick(nick) else {
+        ctx.notice(me, from.uid, format!("\x02{nick}\x02 isn't here."));
+        return;
+    };
+    let reason = if args.len() > 3 { args[3..].join(" ") } else { "Kicked".to_string() };
+    ctx.kick(me, chan, target, &reason);
+}