Move thalamus/ (poc-daemon) source files into src/thalamus/ as a
module of the main crate. The daemon entry point becomes a library
function thalamus::run() with a thin poc-daemon binary for backward
compatibility.
- Copy thalamus source into src/thalamus/, fix crate:: -> super::
- Copy daemon.capnp into schema/, add to build.rs
- Re-export daemon_capnp at crate root (capnp codegen requires it)
- Add thalamus dependencies (capnp-rpc, tokio-util, toml, rustls, etc.)
- Keep thalamus/ subcrate for comparison
Co-Authored-By: Proof of Concept <poc@bcachefs.org>