state: persist the queue and pick up where playback stopped

The queue, its shuffle order and whether playback was running are written to
~/.local/state/rsplayer/state.json whenever they change, and on shutdown, then
restored at daemon start. Tracks that disappeared from disk are dropped
instead of failing on play.

`rsp resume`/`rsp toggle` now start the restored track when nothing is loaded
into the engine yet, which is the state right after a restart with a queue
that was paused.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/main.rs b/src/main.rs
index fd60bef..4bc4498 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -15,6 +15,7 @@ mod notification;
 mod playback;
 mod queue;
 mod scrobbler;
+mod state;
 
 use clap::Parser;
 use cli::Cli;