feat: VST FX rack per-track + masterbus render via native_bridge

app/core/vst_engine.py

@@ -5,6 +5,8 @@ import numpy as np
 import functools
 import threading
 from ctypes import c_char_p
+import subprocess
+
 
 # Native render (bridge/pyfluidsynth) không thread-safe: tuần tự hóa
 RENDER_LOCK = threading.RLock()
@@ -280,6 +282,7 @@ class PluginManager:
         # Synth chỉ quét vst_dir env mặc định /opt/daw_engine/vst3).
         self.extra_vst_dirs = [d for d in (extra_vst_dirs or []) if d]
         self._sf_scan_cache = None  # cache for _scan_soundfonts()
+        self._fx_scan_cache = None  # cache for list_fx()
 
     def _scan_plugins(self) -> dict:
         plugins = {}
@@ -453,6 +456,52 @@ class PluginManager:
             "soundfonts": self._scan_soundfonts()
         }
 
+    def list_fx(self, refresh=False) -> list:
+        """VST3 effect plugins (is_fx) từ native_bridge --scan (SEH-safe).
+
+        Bridge tự phân loại FX/instrument theo VST3 subCategory; VST2 (.dll/.so)
+        không introspect được nên bridge báo instrument — bỏ qua ở đây. Cache
+        process-wide; refresh=True quét lại (Plugins Manager → Scan).
+        """
+        if not refresh and self._fx_scan_cache is not None:
+            return self._fx_scan_cache
+        from app.core.native_render import find_bridge_exe
+        exe = find_bridge_exe()
+        results = []
+        if exe:
+            dirs = [d for d in [self.vst_dir] + self.extra_vst_dirs
+                    if d and os.path.isdir(d)]
+            for d in dirs:
+                try:
+                    r = subprocess.run([exe, "--scan", d], capture_output=True,
+                                       text=True, timeout=300)
+                except Exception:
+                    continue
+                if r.returncode != 0:
+                    continue
+                try:
+                    data = json.loads(r.stdout[r.stdout.find("{"):])
+                except Exception:
+                    continue
+                for p in data.get("plugins", []):
+                    if not p.get("is_fx"):
+                        continue
+                    path = p.get("path", "")
+                    if not path:
+                        continue
+                    name = p.get("name") or os.path.splitext(os.path.basename(path))[0]
+                    results.append({"id": name, "name": name, "path": path,
+                                    "type": p.get("type", "VST3")})
+        seen, uniq = set(), []
+        for fx in results:
+            if fx["path"] in seen:
+                continue
+            seen.add(fx["path"])
+            uniq.append(fx)
+        uniq.sort(key=lambda x: x["name"].lower())
+        self._fx_scan_cache = uniq
+        return uniq
+
     @staticmethod
     def midi_events_to_messages(midi_events: list, bpm: float, sr: int, bank: int = None, program: int = None) -> list:
         beat_duration_sec = 60.0 / max(30.0, bpm)