Fixes #18

Problem

The digit classification demo fails to initialize TensorFlow Lite on devices without Google Play Services.
TfLite.initialize() fails with:
DynamiteModule$LoadingException: No acceptable module com.google.android.gms.tflite_dynamite found.
Local version is 0 and remote version is 0.

Root Cause

The current implementation relies on the Play Services TFLite dynamite module / system runtime, which is unavailable on non-GMS devices.

Changes

• Treat Play Services TFLite initialization failure as non-fatal.
• Add a fallback path to use the bundled TFLite runtime when Play Services is unavailable.
• Add bundled TFLite dependencies to the :subs:ai module.
• Update related interpreter creation call sites accordingly.

Testing

• ./gradlew :subs:ai:assembleDebug
• Manual test on a non-GMS device:
  • Tap init_model -> shows init success
  • Draw digits -> inference works