fix(analysis): native library backfill coordinator for advanced strategy (#881)

* feat(analysis): native library backfill coordinator for advanced strategy

Move advanced analytics scheduling from the webview loop into a Rust
background worker (configure + spawn_blocking batch/enqueue), matching
cover backfill. Scan hash+BPM gap tracks instead of the full library;
suppress low-priority analysis UI events; limit loudness refresh IPC to
the playback window.

* fix(analysis): flat backfill configure IPC and restore probe track-perf

Use flattened Tauri args like cover backfill so release/prod invoke works;
keep emitting analysis:track-perf for library low-priority work so Performance
Probe tpm/last-track stats update while waveform/enrichment UI events stay suppressed.

* chore(analysis): fix clippy and drop duplicate TS backfill policy

Allow too_many_arguments on library_analysis_backfill_configure for CI;
remove unused frontend batch API and TS watermark helpers now owned in Rust;
clarify analysis_emits_ui_events comment for low-priority track-perf.

* docs: CHANGELOG and credits for PR #881 native analysis backfill

src-tauri/crates/psysonic-integration/src/subsonic/mod.rs

@@ -5,12 +5,14 @@
 pub mod auth;
 pub mod client;
 pub mod error;
+pub mod stream_url;
 pub mod types;
 
 pub use auth::SubsonicCredentials;
 pub use client::{
     fingerprint_sample, SubsonicClient, SUBSONIC_API_VERSION, SUBSONIC_CLIENT_ID,
 };
+pub use stream_url::{build_stream_view_url, rest_base_from_url};
 pub use error::SubsonicError;
 pub use types::{
     Album, AlbumSummary, ArtistIndex, ArtistRef, IndexBucket, ScanStatus, SearchResult, ServerInfo,

src-tauri/crates/psysonic-integration/src/subsonic/stream_url.rs

@@ -0,0 +1,61 @@
+//! Subsonic `stream.view` URLs for native library analysis backfill.
+
+use url::Url;
+
+use super::auth::SubsonicCredentials;
+use super::client::{SUBSONIC_API_VERSION, SUBSONIC_CLIENT_ID};
+
+/// `{origin}/rest` — mirrors frontend `restBaseFromUrl`.
+pub fn rest_base_from_url(server_url: &str) -> String {
+    let trimmed = server_url.trim().trim_end_matches('/');
+    let base = if trimmed.starts_with("http://") || trimmed.starts_with("https://") {
+        trimmed.to_string()
+    } else {
+        format!("http://{trimmed}")
+    };
+    format!("{base}/rest")
+}
+
+/// Authenticated `stream.view` URL for a library track id.
+pub fn build_stream_view_url(
+    server_url: &str,
+    username: &str,
+    password: &str,
+    track_id: &str,
+) -> String {
+    let creds = SubsonicCredentials::from_password(username, password);
+    let base = rest_base_from_url(server_url);
+    let mut url =
+        Url::parse(&format!("{base}/stream.view")).unwrap_or_else(|_| Url::parse("http://invalid/rest/stream.view").unwrap());
+    {
+        let mut q = url.query_pairs_mut();
+        q.append_pair("id", track_id);
+        q.append_pair("u", &creds.username);
+        q.append_pair("t", &creds.token);
+        q.append_pair("s", &creds.salt);
+        q.append_pair("v", SUBSONIC_API_VERSION);
+        q.append_pair("c", SUBSONIC_CLIENT_ID);
+        q.append_pair("f", "json");
+    }
+    url.to_string()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn stream_url_contains_track_and_auth_params() {
+        let url = build_stream_view_url(
+            "https://music.example",
+            "alice",
+            "secret",
+            "tr-42",
+        );
+        assert!(url.contains("stream.view"));
+        assert!(url.contains("id=tr-42"));
+        assert!(url.contains("u=alice"));
+        assert!(url.contains("&t="));
+        assert!(url.contains("&s="));
+    }
+}