feat: config module with TOML loading

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_config.py

@@ -0,0 +1,42 @@
+from pathlib import Path
+
+from order_bak.config import load_config
+
+
+def test_load_config_defaults(tmp_path):
+    config_path = tmp_path / "config.toml"
+    config_path.write_text(
+        '[azure]\nconnection_string = "conn_str_val"\n'
+    )
+    cfg = load_config(config_path)
+    assert cfg.azure_connection_string == "conn_str_val"
+    assert cfg.scan_page_size == 500
+    assert cfg.scan_delay_ms == 200
+    assert cfg.scan_dir == Path("./scan")
+    assert cfg.delete_batch_size == 100
+    assert cfg.delete_delay_ms == 300
+
+
+def test_load_config_custom_values(tmp_path):
+    config_path = tmp_path / "config.toml"
+    config_path.write_text(
+        '[azure]\nconnection_string = "conn_str_val"\n'
+        "[scan]\npage_size = 1000\ndelay_ms = 500\nscan_dir = \"/data/scan\"\n"
+        "[delete]\nbatch_size = 50\ndelay_ms = 100\n"
+    )
+    cfg = load_config(config_path)
+    assert cfg.scan_page_size == 1000
+    assert cfg.scan_delay_ms == 500
+    assert cfg.scan_dir == Path("/data/scan")
+    assert cfg.delete_batch_size == 50
+    assert cfg.delete_delay_ms == 100
+
+
+def test_load_config_missing_azure_raises(tmp_path):
+    config_path = tmp_path / "config.toml"
+    config_path.write_text("[scan]\npage_size = 100\n")
+    try:
+        load_config(config_path)
+        assert False, "should have raised"
+    except SystemExit:
+        pass