extract jobkit-daemon library from poc-memory daemon

Create jobkit-daemon crate with generic daemon infrastructure:
- event_log: JSONL append with size-based rotation
- socket: Unix domain socket RPC client and server with signal handling
- status: JSON status file read/write

Migrate daemon.rs to use the library:
- Worker pool setup via Daemon::new()
- Socket loop + signal handling via Daemon::run()
- RPC handlers as registered closures
- Logging, status writing, send_rpc all delegate to library

Migrate tui.rs to use socket::send_rpc() instead of inline UnixStream.

daemon.rs: 1952 → 1806 lines (-146), old status_socket_loop removed.
tui.rs: socket boilerplate removed.

Co-Authored-By: Kent Overstreet <kent.overstreet@linux.dev>

poc-memory/src/tui.rs

@@ -22,8 +22,6 @@ use ratatui::{
     DefaultTerminal, Frame,
 };
 use std::fs;
-use std::io::Read as _;
-use std::os::unix::net::UnixStream;
 use std::path::PathBuf;
 use std::time::{Duration, Instant};
 
@@ -35,10 +33,6 @@ const AGENT_TYPES: &[&str] = &[
     "apply", "orphans", "cap", "digest", "digest-links", "knowledge", "rename", "split",
 ];
 
-fn status_sock_path() -> PathBuf {
-    crate::config::get().data_dir.join("daemon.sock")
-}
-
 fn log_path() -> PathBuf {
     crate::config::get().data_dir.join("daemon.log")
 }
@@ -58,11 +52,8 @@ struct DaemonStatus {
 }
 
 fn fetch_status() -> Option<DaemonStatus> {
-    let mut stream = UnixStream::connect(status_sock_path()).ok()?;
-    stream.set_read_timeout(Some(Duration::from_secs(2))).ok();
-    let mut buf = String::new();
-    stream.read_to_string(&mut buf).ok()?;
-    serde_json::from_str(&buf).ok()
+    let json = jobkit_daemon::socket::send_rpc(&crate::config::get().data_dir, "")?;
+    serde_json::from_str(&json).ok()
 }
 
 #[derive(Clone)]
@@ -794,14 +785,7 @@ fn short_name(name: &str) -> String {
 }
 
 fn send_rpc(cmd: &str) -> Option<String> {
-    let mut stream = UnixStream::connect(status_sock_path()).ok()?;
-    stream.set_write_timeout(Some(Duration::from_secs(2))).ok();
-    stream.set_read_timeout(Some(Duration::from_secs(5))).ok();
-    std::io::Write::write_all(&mut stream, cmd.as_bytes()).ok()?;
-    stream.shutdown(std::net::Shutdown::Write).ok()?;
-    let mut buf = String::new();
-    stream.read_to_string(&mut buf).ok()?;
-    Some(buf)
+    jobkit_daemon::socket::send_rpc(&crate::config::get().data_dir, cmd)
 }
 
 // --- Entry point ---