ctl: interactive shell with history, editing and completion

`rsp ctl` opens a prompt in the spirit of bluetoothctl. Lines are parsed with
the same clap definitions as the one-shot CLI, so every command and flag works
exactly as it does from a terminal, `help <command>` included.

Tab completes subcommands, and track/album/artist paths for `play` through
`db-complete` (run out of process, keeping its 100 ms timeout away from the
input loop). History lives in the state directory. Piped input falls back to a
plain line loop, so `rsp ctl < commands` works without a terminal.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
index 4bc4498..0138ea2 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -8,6 +8,7 @@
 mod audio;
 mod cli;
 mod config;
+mod ctl;
 mod daemon;
 mod database;
 mod mpris;