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>

Cargo.lock

@@ -1437,6 +1437,18 @@ dependencies = [
  "serde_json",
 ]
 
+[[package]]
+name = "jobkit-daemon"
+version = "0.4.0"
+dependencies = [
+ "chrono",
+ "jobkit",
+ "libc",
+ "log",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "jobserver"
 version = "0.1.34"
@@ -1883,6 +1895,7 @@ dependencies = [
  "crossterm",
  "faer",
  "jobkit",
+ "jobkit-daemon",
  "libc",
  "log",
  "memmap2",