feat: load strict JSON configuration files

tests/fixtures/zig-test.jsonadded+8-0

Changes to tests/fixtures/zig-test.json

		@@ -0,0 +1,8 @@
	1	+{
	2	+ "test": {
	3	+ "test_dir": "tests/fixtures",
	4	+ "pattern": "filter_fixture.zig",
	5	+ "recursive": false,
	6	+ "filter": "selected test passes"
	7	+ }
	8	+}