Add production build pipeline (#46)

## Summary
- split development dynamic linking from production builds
- add headless processed-asset generation
- add a separate production CI cache and static Bevy/Rust linkage verification
- keep custom debug features enabled for production builds behind a feature gate

Reviewed-on: #46
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/lib.rs

@@ -155,11 +155,26 @@ impl Plugin for GamePlugin {
     }
 }
 
+/// Registers only the custom asset processors used by CI and release builds.
+/// The processing binary adds this plugin without starting the game.
+pub struct AssetProcessingPlugin;
+
+impl Plugin for AssetProcessingPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_plugins((
+            scripting::importer::FighterScriptImportPlugin,
+            fighter::baked_animation::BakedAnimationAssetProcessingPlugin,
+        ));
+    }
+}
+
 fn wait_for_asset_processor(
     processor: Option<Res<AssetProcessor>>,
     mut next_state: ResMut<NextState<AppState>>,
 ) {
-    if processor.is_none_or(|processor| block_on(processor.get_state()) == ProcessorState::Finished)
+    if !cfg!(feature = "development")
+        || processor
+            .is_none_or(|processor| block_on(processor.get_state()) == ProcessorState::Finished)
     {
         next_state.set(AppState::LoadCommonAssets);
     }