Workstream E: generate bindings.ts via reusable specta_builder + export test

- Extract specta_builder() so run() and a #[test] share one command list.
- Add export_typescript_bindings test that writes src/lib/api/bindings.ts.
- Configure the TS exporter bigint behavior to Number (matches existing frontend).
- Commit the generated bindings.ts (typed commands.* wrappers + all DTO types).

src-tauri/src/lib.rs

@@ -347,14 +347,10 @@ fn create_player_backend(
     }
 }
 
-#[cfg_attr(mobile, tauri::mobile_entry_point)]
-pub fn run() {
-    // Initialize logger
-    env_logger::Builder::from_default_env()
-        .filter_level(log::LevelFilter::Info)
-        .init();
-
-    let builder = Builder::<tauri::Wry>::new()
+/// Construct the tauri-specta command builder. Shared by `run()` and the
+/// bindings-export test so the TypeScript bindings always match the handler.
+fn specta_builder() -> Builder<tauri::Wry> {
+    Builder::<tauri::Wry>::new()
         .commands(tauri_specta::collect_commands![
             // Player commands
             player_play_item,
@@ -580,12 +576,22 @@ pub fn run() {
             convert_ticks_to_seconds,
             calc_progress,
             convert_percent_to_volume,
-        ]);
+        ])
+}
+
+#[cfg_attr(mobile, tauri::mobile_entry_point)]
+pub fn run() {
+    // Initialize logger
+    env_logger::Builder::from_default_env()
+        .filter_level(log::LevelFilter::Info)
+        .init();
+
+    let builder = specta_builder();
 
     // Export TypeScript bindings (types + typed invoke wrappers) in dev builds.
     #[cfg(debug_assertions)]
     builder
-        .export(specta_typescript::Typescript::default(), "../src/lib/api/bindings.ts")
+        .export(specta_typescript::Typescript::default().bigint(specta_typescript::BigIntExportBehavior::Number), "../src/lib/api/bindings.ts")
         .expect("Failed to export typescript bindings");
 
     tauri::Builder::default()
@@ -835,3 +841,18 @@ pub fn run() {
         .run(tauri::generate_context!())
         .expect("error while running tauri application");
 }
+
+
+#[cfg(test)]
+mod specta_bindings {
+    /// Generates `src/lib/api/bindings.ts`. Run with `cargo test export_typescript_bindings`.
+    #[test]
+    fn export_typescript_bindings() {
+        super::specta_builder()
+            .export(
+                specta_typescript::Typescript::default().bigint(specta_typescript::BigIntExportBehavior::Number),
+                "../src/lib/api/bindings.ts",
+            )
+            .expect("failed to export typescript bindings");
+    }
+}