Phase 3: engine render chain hop nhat — track/master doc mastering_settings.chain (imager/maximizer), PDC probe FX_LATENCIES, fix daw_vst_bridge link BuiltinFxChain, pytest 3.2/3.3

app/core/native_render.py

@@ -216,12 +216,14 @@ def render_offline(instrument_id, notes, bpm, sample_rate, preset_id=None,
                 pass
 
 
-def render_fx_chain(input_wav, fx_chain, sample_rate, out_path=None) -> str:
+def render_fx_chain(input_wav, fx_chain, sample_rate, out_path=None):
     """Render WAV qua native_bridge --render-fx (VST3 FX + builtin gain/normalize).
 
     fx_chain: list dict {type: "vst3"|"builtin", path|id, preset_b64?, bypass?,
     params?}. path là plugin id/name → resolve_plugin_path (".vst3"). Trả
-    out_path; lỗi → HTTPException (501 thiếu bridge, 404 plugin lạ, 500 render).
+    (out_path, latencies) — latencies: per-slot samples (bridge FX_LATENCIES,
+    Phase 3 PDC; [] nếu exe cũ không báo). Lỗi → HTTPException (501 thiếu
+    bridge, 404 plugin lạ, 500 render).
     """
     from app.core.vst_engine import resolve_plugin_path
     exe = find_fx_bridge_exe()
@@ -284,7 +286,16 @@ def render_fx_chain(input_wav, fx_chain, sample_rate, out_path=None) -> str:
                                     detail=f"Bridge không load được plugin. {log[-500:]}")
             raise HTTPException(status_code=500,
                                 detail=f"FX render thất bại (rc={r.returncode}). {log[-500:]}")
-        return out
+        latencies = []
+        for _line in (r.stdout or "").splitlines():
+            if "FX_LATENCIES" in _line:
+                try:
+                    latencies = [int(x) for x in
+                                 _line.split("FX_LATENCIES", 1)[1].split()]
+                except Exception:
+                    latencies = []
+                break
+        return out, latencies
     except HTTPException:
         raise
     except subprocess.TimeoutExpired: