feat: native host bridge integration — C++ bridge, Rust SHM, JS routing, build scripts, docs

- native_bridge/: InstrumentEngineManager multi-channel, sample-accurate, CC/program/pitchbend, transport, Vst3Instrument stub (HAVE_VST3SDK)
- src-tauri: shm.rs, bridge spawn + audio pump + health monitor, open_vst_gui, externalBin, commands
- app: UnifiedMidiRouter, NativeBridgeService, bridgeAudioNode, audioRoutingEngine, Plugin Manager UI, Bridge/WASM indicator, set_position sync
- build: 3 ps1 (force-added, build/ ignored), verify_bundle --check-bridge, CI workflow
- docs: TASKS.md, TEST_NOTES.md (Windows verify checklist), install/report updates

tools/verify_bundle.py

@@ -14,6 +14,11 @@ import re
 import sys
 
 REQUIRED = ["app/static", "app/templates"]
+# F4: bridge sidecar phai co truoc khi tauri build (externalBin). Kiem tra tai
+# day de build fail SOM nhat (build_windows.ps1 goi verify nay truoc tauri build).
+BRIDGE_SIDECAR = os.path.join(
+    "src-tauri", "binaries", "daw_vst_bridge-x86_64-pc-windows-msvc.exe"
+)
 
 
 def find_toc(build_dir: str) -> str:
@@ -31,6 +36,7 @@ def find_toc(build_dir: str) -> str:
 
 
 def main() -> int:
+    check_bridge = "--check-bridge" in sys.argv
     build_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "build"))
     toc = find_toc(build_dir)
     if not toc:
@@ -54,6 +60,19 @@ def main() -> int:
         print(f"ERROR: Bundle thieu: {', '.join(missing)}. Kiem tra engine.spec datas!")
         return 1
     print("OK: app/static + app/templates co trong bundle.")
+    # F4: bridge sidecar (externalBin) — kiem tra o repo root (khong phai trong
+    # PyInstaller bundle): thieu -> tauri build se im lang bo qua bridge.
+    # Chi chay khi --check-bridge (goi o buoc [7/7] build_windows.ps1 — sau
+    # khi da build bridge o buoc [5/7]).
+    if check_bridge:
+        repo_root = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
+        sidecar = os.path.join(repo_root, BRIDGE_SIDECAR)
+        if not os.path.exists(sidecar):
+            print(f"ERROR: Thieu bridge sidecar: {sidecar}")
+            print("       Chay build/scripts/build_native_bridge.ps1 truoc, hoac")
+            print("       build_windows.ps1 buoc [5/7] se build tu dong.")
+            return 1
+        print(f"OK: bridge sidecar co mat ({BRIDGE_SIDECAR}).")
     return 0