Group the module crates under modules/

The service pseudo-clients and the ircd protocol link sat flat at the
repo root, mixed in with the daemon core and the SDK. Move them all
under modules/ so the tree separates concerns cleanly: the daemon in
src/, the SDK every module links against in api/, and the loadable
modules — the pseudo-clients plus the protocol link — in modules/.

Workspace members, the daemon's per-crate dependency paths, and each
module's api path are updated to match; the docs follow. No code change.

modules/chanserv/src/topic.rs

@@ -0,0 +1,16 @@
+use fedserv_api::Store;
+use fedserv_api::{Sender, ServiceCtx};
+
+// TOPIC <#channel> <text>: set the channel topic (empty clears it).
+pub fn handle(me: &str, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, db: &dyn Store) {
+    let Some(&chan) = args.get(1) else {
+        ctx.notice(me, from.uid, "Syntax: TOPIC <#channel> <text>");
+        return;
+    };
+    if !super::require_op(me, from, chan, ctx, db) {
+        return;
+    }
+    let text = if args.len() > 2 { args[2..].join(" ") } else { String::new() };
+    ctx.topic(me, chan, &text);
+    ctx.notice(me, from.uid, format!("Topic for \x02{chan}\x02 updated."));
+}