Clean up internals, fix bugs, add tests + CI (#15)

* Remove internal code: training, dataset, benchmarks, root-level scripts

* [Build] Add load_cnn_model to predictor.py, fix weights_only=True, break circular import

* [Build] Fix batch_infer.py: update import, fix indent, remove pass, guard cuda, organize imports

* [Build] Fix hcqm.py: change default device to None, resolve with get_device()

* [Build] Deduplicate utils.py: split_audio as core, load_and_split_audio as wrapper

* [Build] Add __init__.py files, fix re-export, update pyproject.toml

* Fix import ordering across all source files

* [Build] Add tests and CI workflow

Author: bleugreen

.github/workflows/ci.yml

@@ -0,0 +1,26 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  lint-and-test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.10"
+
+      - name: Install dependencies
+        run: pip install -e ".[dev]" soundfile
+
+      - name: Lint
+        run: ruff check src/
+
+      - name: Test
+        run: pytest