Fix decoder panic on streamed network tracks

Playing a network track panicked in rodio 0.22's symphonia backend:
"Seek errors should not occur during initialization". During init
symphonia probes the container length; on a source with no known byte
length it seeks from the end, and StreamDownload handles that in a way
rodio turns into an `unreachable!`. This surfaced after the dependency
bump from rodio 0.17 (with the old custom SymphoniaDecoder) to 0.22.

Pass the stream's content length to the decoder via with_byte_len (the
local-file path already did this), which lets symphonia skip the
end-relative seek entirely. Verified against a real Tidal AAC/mp4
stream: the streamed decode now succeeds instead of panicking.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

audio-player/src/player_engine.rs

@@ -208,7 +208,15 @@ impl PlayerEngine {
                     .map_err(|_| anyhow!("timed out opening stream after {STREAM_OPEN_TIMEOUT:?}"))?
                     .context("failed to open http stream")
                 })?;
+                // Symphonia probes the container length during init; without a
+                // known byte length it seeks from the end, which rodio 0.22 turns
+                // into an `unreachable!` panic on a streamed source. Handing it the
+                // content length up front avoids that seek entirely.
+                let byte_len = reader.content_length();
                 let mut builder = Decoder::builder().with_data(reader).with_seekable(true);
+                if let Some(len) = byte_len {
+                    builder = builder.with_byte_len(len);
+                }
                 if let Some(extension) = Path::new(url.path()).extension().and_then(|e| e.to_str())
                 {
                     builder = builder.with_hint(extension);