Fix 3 bug standalone: save project lỗi schema, export MIDI/WAV không hỏi nơi lưu

- Bug 1: serializeTracksList bỏ section item không có sectionId (do insertSectionAtPlayhead tạo) — tránh source_data {} làm schema oneOf fail
- Bug 2: export MIDI qua save-dialog + write file, toast kèm đường dẫn
- Bug 3: export mix WAV/MP3/OGG qua save-dialog + write file, toast kèm đường dẫn
- Marker tauri_bridge_ready: xóa khi window destroy + guard SF_PARENT_PID — tránh standalone treo 120s

app/api/v1/files.py

@@ -0,0 +1,128 @@
+import os, sys, json, subprocess, time as _time
+from fastapi import APIRouter, HTTPException, UploadFile, File, Form
+from pydantic import BaseModel
+from typing import Optional
+
+router = APIRouter()
+
+# ── Native "Save As" dialog (fix bug: export MIDI/WAV không hỏi nơi lưu) ──
+# WebView2 standalone chặn anchor-download → không thấy save dialog. Giải pháp:
+# frontend gọi /save-dialog → engine mở NATIVE SaveFileDialog (Windows Explorer)
+# → trả đường dẫn user chọn → frontend gửi bytes qua /write → ghi file thật.
+SAVE_DIALOG_TIMEOUT = 120  # user có thể để dialog mở lâu
+
+
+def _save_file_via_tauri_bridge(default_name: str) -> Optional[str]:
+    """Tauri shell (Rust watcher trong lib.rs) mở NATIVE SaveFileDialog qua
+    file IPC: engine ghi save_file.request (chứa tên mặc định) → Rust mở dialog
+    → ghi save_file.response. Trả None nếu bridge không tồn tại (standalone)."""
+    root = os.environ.get("APPDATA") or os.path.expanduser("~")
+    ipc = os.path.join(root, "SonicForgeDAW", "ipc")
+    if not os.path.isdir(ipc):
+        return None
+    # Bridge chi dung khi engine do Tauri spawn (co SF_PARENT_PID). Marker co
+    # the con sot tu lan Tauri chay truoc → chay standalone se cho response
+    # khong bao gio den (treo 120s). Check nay loai bo truong hop do.
+    if not os.environ.get("SF_PARENT_PID"):
+        return None
+    if not os.path.exists(os.path.join(ipc, "tauri_bridge_ready")):
+        return None
+    req = os.path.join(ipc, "save_file.request")
+    resp = os.path.join(ipc, "save_file.response")
+    try:
+        for f in (req, resp):
+            if os.path.exists(f):
+                os.remove(f)
+        with open(req, "w", encoding="utf-8") as fh:
+            fh.write(default_name or "untitled")
+        deadline = _time.time() + SAVE_DIALOG_TIMEOUT
+        while _time.time() < deadline:
+            if os.path.exists(resp):
+                try:
+                    with open(resp, "r", encoding="utf-8") as fh:
+                        val = fh.read().strip()
+                finally:
+                    os.remove(resp)
+                return val or None
+            _time.sleep(0.1)
+    except Exception:
+        pass
+    return None
+
+
+def _save_file_native_engine(default_name: str, filter_name: str, filter_ext: str) -> Optional[str]:
+    """Fallback khi không có Tauri bridge: PowerShell SaveFileDialog (Windows),
+    osascript (macOS), zenity/kdialog (Linux)."""
+    if os.name == "nt":
+        # FileName mặc định + Filter — single-quoted trong PS, filename không
+        # chứa nháy đơn (SonicForge tự sinh tên).
+        ps = (
+            "Add-Type -AssemblyName System.Windows.Forms; "
+            f"$f = New-Object System.Windows.Forms.SaveFileDialog; "
+            f"$f.FileName = '{default_name}'; "
+            f"$f.Filter = '{filter_name} (*.{filter_ext})|*.{filter_ext}|Tất cả các tệp (*.*)|*.*'; "
+            "$f.Title = 'Chọn nơi lưu tệp xuất'; "
+            "if ($f.ShowDialog() -eq [System.Windows.Forms.DialogResult]::OK) { Write-Output $f.FileName }"
+        )
+        try:
+            r = subprocess.run(
+                ["powershell", "-NoProfile", "-STA", "-Command", ps],
+                capture_output=True, text=True, timeout=SAVE_DIALOG_TIMEOUT,
+            )
+            return r.stdout.strip() or None
+        except Exception:
+            return None
+    if sys.platform == "darwin":
+        try:
+            r = subprocess.run(
+                ["osascript", "-e",
+                 'set f to choose file name with prompt "Chọn nơi lưu tệp xuất" default name "' + (default_name or "untitled") + '"'],
+                capture_output=True, text=True, timeout=SAVE_DIALOG_TIMEOUT,
+            )
+            return r.stdout.strip() or None
+        except Exception:
+            return None
+    for cmd in (["zenity", "--file-selection", "--save", "--filename=" + (default_name or "untitled")],
+                ["kdialog", "--getsavefilename", os.path.join(os.path.expanduser("~"), default_name or "untitled")]):
+        try:
+            r = subprocess.run(cmd, capture_output=True, text=True, timeout=SAVE_DIALOG_TIMEOUT)
+            if r.returncode == 0:
+                p = r.stdout.strip()
+                if p:
+                    return p
+        except Exception:
+            continue
+    return None
+
+
+class SaveDialogRequest(BaseModel):
+    default_name: str = "untitled"
+    filter_name: str = "File"
+    filter_ext: str = "bin"
+
+
+@router.post("/save-dialog")
+def save_file_dialog(req: SaveDialogRequest):
+    """Mở NATIVE Save As dialog. Không cần auth (desktop local, chỉ mở dialog).
+    Trả {"path": "<đường dẫn user chọn>"} hoặc {"path": None} (hủy/không có
+    dialog). def (sync) → FastAPI chạy threadpool — không block loop."""
+    path = _save_file_via_tauri_bridge(req.default_name)
+    if path is None:
+        path = _save_file_native_engine(req.default_name, req.filter_name, req.filter_ext)
+    return {"path": path}
+
+
+@router.post("/write")
+async def write_export_file(path: str = Form(...), file: UploadFile = File(...)):
+    """Ghi bytes đã export vào đường dẫn tuyệt đối user chọn qua save dialog.
+    Trả {"path": ..., "bytes": N} — frontend toast kèm đường dẫn thật."""
+    try:
+        data = await file.read()
+        dirname = os.path.dirname(path)
+        if dirname:
+            os.makedirs(dirname, exist_ok=True)
+        with open(path, "wb") as f:
+            f.write(data)
+        return {"path": path, "bytes": len(data)}
+    except Exception as e:
+        raise HTTPException(status_code=400, detail=f"Không thể ghi file: {str(e)}")

app/api/v1/plugins.py

@@ -277,6 +277,11 @@ def _pick_dir_via_tauri_bridge() -> Optional[str]:
     ipc = os.path.join(root, "SonicForgeDAW", "ipc")
     if not os.path.isdir(ipc):
         return None
+    # Bridge chi dung khi engine do Tauri spawn (co SF_PARENT_PID). Marker co
+    # the con sot tu lan Tauri chay truoc → chay standalone se cho response
+    # khong bao gio den (treo 120s). Check nay loai bo truong hop do.
+    if not os.environ.get("SF_PARENT_PID"):
+        return None
     # Marker do Rust viết lúc setup — bridge chỉ có trong app Tauri desktop
     if not os.path.exists(os.path.join(ipc, "tauri_bridge_ready")):
         return None