seek: jump within the current track from the CLI and over MPRIS

`rsp seek 1:30`, `rsp seek +15`, `rsp seek -30` and `rsp seek` (print the
position) drive a new AudioCommand that seeks the format reader, resets the
decoder and drops the buffered samples, so the cpal stream keeps running and
playback continues from the new spot.

MPRIS gets a working Seek/SetPosition, reports CanSeek, and the state watcher
now emits Seeked when the playhead jumps (not just on track changes), which is
what clients need to move their progress bar after an external seek.

`rsp status` also reports the position (and duration when known) and says
Paused instead of Stopped when a track is loaded but not playing.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/cli.rs b/src/cli.rs
index 12bc3b0..79c31a8 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -68,6 +68,13 @@ pub enum Commands {
     Queue,
     /// Show player status
     Status,
+    /// Seek within the current track
+    Seek {
+        /// Position: `90`, `1:30`, `1:02:03`, or a relative offset `+15` / `-30`;
+        /// without one, the current position is printed
+        #[arg(value_name = "POSITION", allow_hyphen_values = true)]
+        position: Option<String>,
+    },
     /// Scan music paths to populate database
     Scan {
         #[arg(long)]
@@ -198,6 +205,10 @@ impl Cli {
             Commands::Status => {
                 crate::daemon::send_command("status".to_string())?;
             }
+            Commands::Seek { position } => match position {
+                Some(p) => crate::daemon::send_command(format!("seek {}", p))?,
+                None => crate::daemon::send_command("seek".to_string())?,
+            },
             Commands::Scan { force, paths } => {
                 let config = Config::load()?;
                 let db = Database::open(&config)?;