Bootstrap the repixelizer CLI project

tests/test_cli.py

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+from __future__ import annotations
+
+from pathlib import Path
+
+from repixelizer.cli import main
+from repixelizer.io import save_rgba
+from repixelizer.synthetic import fake_pixelize, make_emblem
+
+
+def test_default_command_runs_without_explicit_run_subcommand(tmp_path: Path) -> None:
+    source = make_emblem(16, 16)
+    fake = fake_pixelize(source, upscale=8, phase_x=0.2, phase_y=0.25, blur_radius=0.4)
+    input_path = tmp_path / "input.png"
+    output_path = tmp_path / "output.png"
+    save_rgba(input_path, fake)
+    exit_code = main([str(input_path), "--out", str(output_path), "--steps", "8"])
+    assert exit_code == 0
+    assert output_path.exists()