perf: slim daw_engine bundle 409MB->170MB + fix engine khong chay tren Windows

- Thay librosa bang app/core/audio_features.py (numpy/scipy/soundfile):
  load, beat_track, frames_to_time, spectral_centroid, rms, zero_crossing_rate,
  time_stretch, pitch_shift, chroma_stft. A/B ngang librosa (BPM <1% sai lech,
  pitch_shift chuan toi Hz). Loai bo llvmlite 171MB + scikit-learn + numba.
- Task layer 2 che do (app/tasks/worker.py): server giu celery; desktop slim
  chay in-process thread + registry, giu nguyen API contract (.delay/.id/status
  /tasks/{id}) nen frontend khong doi.
- engine.spec: excludes librosa/numba/llvmlite/sklearn/celery/redis/kombu/
  billiard/amqp/msgpack/yaml/PIL/cairosvg/zstandard/...; scan scipy gioi han
  scipy.signal; giu click (uvicorn.main import click).
- render_engine: scipy.signal thanh lazy import (giam cold start).
- tauri.conf.json: targets [nsis, msi] - NSIS tro lai (bundle nho) de
  hooks.nsh cai VC++ Redistributable - sua bug daw_engine.exe khong chay
  tren Windows (truoc day MSI-only khong chay hooks).
- build_linux.sh / build_macos.sh: build 1 lenh moi OS.
- Doc: DESKTOP_INSTALL_PLAN.md muc 5.1.
- Verify: 86 tests pass, engine dong goi upload/analyze/waveform/export OK.

build_macos.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+# build_macos.sh - build daw_engine (PyInstaller ONEDIR) + Tauri v2 (.app + .dmg)
+# Chay tren macOS: bash build_macos.sh
+# LUU Y: macOS yeu cau codesign + notarize truoc khi phat hanh ra ngoai
+# (Gatekeeper). Xem DISTRIBUTION_PLAN.md.
+set -euo pipefail
+cd "$(dirname "$0")"
+
+echo "== [1/6] Python dependencies =="
+python3 -m pip install --upgrade pip >/dev/null
+python3 -m pip install -r requirements.txt pyinstaller
+
+echo "== [2/6] Frontend bundle =="
+npm install --no-audit --no-fund
+if [ ! -d "node_modules/@babel/standalone" ]; then
+  npm install @babel/standalone --no-audit --no-fund
+fi
+node build.mjs
+
+echo "== [3/6] Build daw_engine (PyInstaller ONEDIR) =="
+python3 -m PyInstaller engine.spec --clean --noconfirm
+
+echo "== [3.5/6] Verify bundle contents =="
+python3 tools/verify_bundle.py || { echo "ERROR: Bundle thieu asset - dung build!"; exit 1; }
+
+echo "== [4/6] Copy onedir engine -> src-tauri/resources/daw_engine =="
+if [ ! -f "dist/daw_engine/daw_engine" ]; then
+  echo "ERROR: dist/daw_engine/daw_engine khong ton tai (onedir build loi?)"
+  exit 1
+fi
+rm -rf src-tauri/resources/daw_engine
+mkdir -p src-tauri/resources/daw_engine
+cp -a dist/daw_engine/. src-tauri/resources/daw_engine/
+echo "Copied onedir engine -> src-tauri/resources/daw_engine"
+
+echo "== [5/6] Kiem tra resources =="
+if [ ! -f "src-tauri/resources/daw_engine/daw_engine" ] || [ ! -d "src-tauri/resources/daw_engine/_internal" ]; then
+  echo "ERROR: thieu src-tauri/resources/daw_engine/{daw_engine,_internal}"
+  exit 1
+fi
+
+echo "== [6/6] Tauri build (dmg) =="
+npm install -D @tauri-apps/cli --no-audit --no-fund
+npx tauri build
+
+echo ""
+echo "== DONE =="
+echo "  dmg: src-tauri/target/release/bundle/dmg/SonicForgeDAW_1.0.0_x64.dmg"
+echo "  (Codesign/notarize: codesign --deep -s \"Developer ID Application: ...\" "
+echo "   src-tauri/target/release/bundle/macos/SonicForgeDAW.app ; xcrun notarytool submit ...)"