rename: poc-agent → agent, poc-daemon → thalamus

The thalamus: sensory relay, always-on routing. Perfect name for the
daemon that bridges IRC, Telegram, and the agent.

Co-Authored-By: Proof of Concept <poc@bcachefs.org>

thalamus/build.rs

@@ -0,0 +1,6 @@
+fn main() {
+    capnpc::CompilerCommand::new()
+        .file("schema/daemon.capnp")
+        .run()
+        .expect("capnp compile failed");
+}