Add scrobbling support (Last.fm + ListenBrainz) and rsp settings reload

- Full Last.fm API implementation with MD5 signing (track.updateNowPlaying, track.scrobble)
- Full ListenBrainz API implementation (/1/submit-listens for playing_now and single)
- ScrobbleState in daemon tracking track, start time, and unix timestamp per play
- Scrobble threshold: ≥30s play AND (≥half duration OR ≥4 min)
- Duration extraction from symphonia codec params into AudioMetadata and Track
- Token validation at daemon startup and on config change
- ListenBrainz token valid (user: Salmonium) command to re-read config from disk (avoids token in shell history)
- Desktop notifications for token validation results
- Empty-credential filtering (empty string = no-op)

1 files changed, 19 insertions, 1 deletions

diff --git a/src/queue.rs b/src/queue.rs
index d42203f..8f98173 100644
--- a/src/queue.rs
+++ b/src/queue.rs
@@ -13,6 +13,7 @@ pub struct AudioMetadata {
     pub title: Option<String>,
     pub artist: Option<String>,
     pub album: Option<String>,
+    pub duration_secs: Option<f64>,
 }
 
 pub fn extract_metadata(path: &Path) -> Option<AudioMetadata> {
@@ -28,7 +29,22 @@ pub fn extract_metadata(path: &Path) -> Option<AudioMetadata> {
         .format(&hint, mss, &Default::default(), &Default::default())
         .ok()?;
 
-    let mut metadata = AudioMetadata::default();
+    // Extract duration from format track's codec parameters
+    let duration_secs = probed
+        .format
+        .tracks()
+        .iter()
+        .find(|t| t.codec_params.n_frames.is_some() && t.codec_params.time_base.is_some())
+        .and_then(|t| {
+            let n_frames = t.codec_params.n_frames?;
+            let tb = t.codec_params.time_base?;
+            Some(n_frames as f64 * tb.numer as f64 / tb.denom as f64)
+        });
+
+    let mut metadata = AudioMetadata {
+        duration_secs,
+        ..Default::default()
+    };
 
     if let Some(meta) = probed.metadata.get()
         && let Some(rev) = meta.current()
@@ -82,6 +98,7 @@ pub struct Track {
     pub title: Option<String>,
     pub artist: Option<String>,
     pub album: Option<String>,
+    pub duration_secs: Option<f64>,
 }
 
 impl Track {
@@ -93,6 +110,7 @@ impl Track {
             title: metadata.and_then(|m| m.title.clone()),
             artist: metadata.and_then(|m| m.artist.clone()),
             album: metadata.and_then(|m| m.album.clone()),
+            duration_secs: metadata.and_then(|m| m.duration_secs),
         }
     }