feat: migrate on-device Qwen3 ASR to CoreML for background Flow dictation

Replace MLX GPU inference with CoreML bundles so transcription continues
while the host app is backgrounded. Adds model download and warm-up,
vendored Qwen3Speech, and updates onboarding, settings, and copy for the
~1.6 GB CoreML package (iOS 18+).

Scripts/generate-xcodeproj.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# Generate OSGKeyboard.xcodeproj from project.yml and apply the Icon Composer
+# patch required by XcodeGen 2.43.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
+
+xcodegen generate
+"$ROOT/Scripts/patch-icon-composer.sh"