test: persistence e2e and registration-relogin e2e; lint clean

Adds a lib target (soulseek_rs_tui) exposing cli/models/persist so
integration tests can drive the persistence pipeline: state and config
survive a simulated restart through the real files, with the incomplete
download flagged for auto-resume. The lib e2e suite gains a
register-then-relogin test against soulfind proving the stored-credential
flow's server assumptions. cargo clippy --all-targets and cargo fmt are
clean.

soulseek-rs/src/persist/config.rs

@@ -5,7 +5,7 @@ use std::path::Path;
 /// Optional settings read from `config.toml`. Every field is optional so a
 /// partial file (or none at all) is valid; unknown keys are ignored so newer
 /// configs still load in older builds.
-#[derive(Debug, Default, Clone, PartialEq, Serialize, Deserialize)]
+#[derive(Debug, Default, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(default)]
 pub struct FileConfig {
     pub username: Option<String>,
@@ -54,7 +54,7 @@ impl FileConfig {
 
 /// Fully-resolved settings after layering CLI (which already includes env via
 /// clap) over the config file over built-in defaults.
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Resolved {
     pub username: Option<String>,
     pub server: String,
@@ -73,10 +73,12 @@ pub const DEFAULT_DOWNLOAD_DIR: &str = "~/Downloads";
 pub const DEFAULT_MAX_CONCURRENT_DOWNLOADS: usize = 5;
 pub const DEFAULT_SEARCH_TIMEOUT: u64 = 10;
 
-/// Layer CLI/env values over the config file over defaults. The
-/// `--disable-listener` flag can only enable the disable (a bare flag has no
-/// "explicitly off" form), so file `disable_listener = true` wins unless the
-/// flag is passed.
+/// Layer CLI/env values over the config file over defaults.
+///
+/// The `--disable-listener` flag can only enable the disable (a bare flag
+/// has no "explicitly off" form), so file `disable_listener = true` wins
+/// unless the flag is passed.
+#[must_use]
 pub fn resolve(cli: &crate::cli::Cli, file: &FileConfig) -> Resolved {
     Resolved {
         username: cli.username.clone().or_else(|| file.username.clone()),

soulseek-rs/src/persist/paths.rs

@@ -4,6 +4,7 @@ use std::path::PathBuf;
 /// Platform-appropriate locations for the config file and state directory.
 /// Overridable via `SOULSEEK_CONFIG_DIR` / `SOULSEEK_STATE_DIR` (used by the
 /// e2e tests, and handy for portable installs).
+#[must_use]
 pub fn config_file() -> Option<PathBuf> {
     if let Ok(dir) = std::env::var("SOULSEEK_CONFIG_DIR") {
         return Some(PathBuf::from(dir).join("config.toml"));
@@ -11,6 +12,7 @@ pub fn config_file() -> Option<PathBuf> {
     project_dirs().map(|d| d.config_dir().join("config.toml"))
 }
 
+#[must_use]
 pub fn state_dir() -> Option<PathBuf> {
     if let Ok(dir) = std::env::var("SOULSEEK_STATE_DIR") {
         return Some(PathBuf::from(dir));

soulseek-rs/src/persist/secret.rs

@@ -32,9 +32,10 @@ impl SecretStore for KeyringStore {
     }
 }
 
-/// Resolve the password with precedence: CLI/env (`cli_password`, already
-/// merged by clap) > OS keychain > `password_cmd` from config.toml. Returns
-/// `None` when no source has one — the caller shows the login screen.
+/// Resolve the password with precedence: CLI/env > keychain > `password_cmd`.
+///
+/// `cli_password` already has env merged in by clap. Returns `None` when no
+/// source has one — the caller shows the login screen.
 ///
 /// Keychain errors are downgraded to "not found": on headless boxes without
 /// a secret service the fallbacks must still work.

soulseek-rs/src/persist/snapshot.rs

@@ -17,6 +17,7 @@ impl Snapshot {
     /// Extract what should survive a restart. Downloads that are not yet
     /// `Completed` (including failed/timed-out ones) are marked incomplete
     /// so the next start can re-enqueue them.
+    #[must_use]
     pub fn capture(state: &AppState) -> Self {
         let downloads = state
             .downloads
@@ -25,10 +26,7 @@ impl Snapshot {
                 username: entry.download.username.clone(),
                 filename: entry.download.filename.clone(),
                 size: entry.download.size,
-                download_directory: entry
-                    .download
-                    .download_directory
-                    .clone(),
+                download_directory: entry.download.download_directory.clone(),
                 completed: matches!(
                     entry.download.status,
                     DownloadStatus::Completed
@@ -43,8 +41,12 @@ impl Snapshot {
             }
         }
 
-        let rooms =
-            state.rooms.open.iter().map(|room| room.name.clone()).collect();
+        let rooms = state
+            .rooms
+            .open
+            .iter()
+            .map(|room| room.name.clone())
+            .collect();
 
         Self {
             downloads,
@@ -80,10 +82,7 @@ mod tests {
     use std::sync::{Arc, mpsc};
     use std::time::Instant;
 
-    fn download(
-        filename: &str,
-        status: DownloadStatus,
-    ) -> DownloadEntry {
+    fn download(filename: &str, status: DownloadStatus) -> DownloadEntry {
         let (sender, _receiver) = mpsc::channel();
         DownloadEntry {
             download: Download {
@@ -114,8 +113,12 @@ mod tests {
     #[test]
     fn capture_maps_download_status_to_completed_flag() {
         let mut state = AppState::new();
-        state.downloads.push(download("done.mp3", DownloadStatus::Completed));
-        state.downloads.push(download("queued.mp3", DownloadStatus::Queued));
+        state
+            .downloads
+            .push(download("done.mp3", DownloadStatus::Completed));
+        state
+            .downloads
+            .push(download("queued.mp3", DownloadStatus::Queued));
         state.downloads.push(download(
             "failed.mp3",
             DownloadStatus::Failed(Some("nope".into())),

soulseek-rs/src/persist/state.rs

@@ -29,7 +29,8 @@ pub struct StateStore {
 }
 
 impl StateStore {
-    pub fn new(dir: PathBuf) -> Self {
+    #[must_use]
+    pub const fn new(dir: PathBuf) -> Self {
         Self { dir }
     }
 
@@ -198,9 +199,7 @@ mod tests {
     fn migrations_upgrade_old_data() {
         // Machinery test with a synthetic chain: v0 stored plain strings,
         // v1 wraps each in an object {"name": ...}.
-        #[derive(
-            Debug, PartialEq, Default, Serialize, serde::Deserialize,
-        )]
+        #[derive(Debug, PartialEq, Default, Serialize, serde::Deserialize)]
         struct Named {
             name: String,
         }
@@ -216,15 +215,11 @@ mod tests {
         }];
         let tmp = tempfile::tempdir().unwrap();
         let path = tmp.path().join("things.json");
-        std::fs::write(&path, r#"{"version": 0, "data": ["a", "b"]}"#)
-            .unwrap();
+        std::fs::write(&path, r#"{"version": 0, "data": ["a", "b"]}"#).unwrap();
         let loaded: Vec<Named> = load(&path, chain);
         assert_eq!(
             loaded,
-            vec![
-                Named { name: "a".into() },
-                Named { name: "b".into() }
-            ]
+            vec![Named { name: "a".into() }, Named { name: "b".into() }]
         );
     }