split into workspace: poc-memory and poc-daemon subcrates

poc-daemon (notification routing, idle timer, IRC, Telegram) was already
fully self-contained with no imports from the poc-memory library. Now it's
a proper separate crate with its own Cargo.toml and capnp schema.

poc-memory retains the store, graph, search, neuro, knowledge, and the
jobkit-based memory maintenance daemon (daemon.rs).

Co-Authored-By: ProofOfConcept <poc@bcachefs.org>

build.rs

@@ -1,11 +0,0 @@
-fn main() {
-    capnpc::CompilerCommand::new()
-        .file("schema/memory.capnp")
-        .run()
-        .expect("capnp compile failed");
-
-    capnpc::CompilerCommand::new()
-        .file("schema/daemon.capnp")
-        .run()
-        .expect("capnp compile failed");
-}