Add stream HRTF inputs and drop unused renderer gain

src/api/joc_stream_api.cpp

@@ -33,6 +33,16 @@ joc::stream::Config to_config(const joc_stream_config& config) {
     }
     out.gain_db = config.gain_db;
     out.native_threads = config.native_threads;
+    // The binaural HRTF inputs of joc_task_config, copied with the same defaults:
+    // the policy is taken verbatim (0 is "none", a real choice, not "unset") and
+    // the radius keeps its documented default of 1.0 when the field is not set.
+    if (config.hrtf_sofa_path != nullptr) { out.hrtf_sofa_path = config.hrtf_sofa_path; }
+    if (config.personalized_headphone_path != nullptr) {
+        out.personalized_headphone_path = config.personalized_headphone_path;
+    }
+    if (config.hrtf_cache_dir != nullptr) { out.hrtf_cache_dir = config.hrtf_cache_dir; }
+    out.hrtf_cache_policy = config.hrtf_cache_policy;
+    if (config.hrtf_radius_m > 0.0) { out.hrtf_radius_m = config.hrtf_radius_m; }
     return out;
 }