refactor: split integration.c into modular test files

Co-authored-by: aider (deepseek/deepseek-reasoner) <aider@aider.chat>

tests/main.c

@@ -0,0 +1,32 @@
+#include "test_common.h"
+
+/* Declare test group functions */
+int test_audio(void);
+int test_loop(void);
+int test_channel(void);
+int test_scene_all(void);
+int test_fifo(void);
+
+int main(void) {
+    if (system("test -x ./looper") != 0) {
+        fprintf(stderr, "FATAL: looper binary not found\n");
+        return 1;
+    }
+
+    int failures = 0;
+
+    /* Audio pass‑through (non‑fatal) */
+    test_audio();
+
+    failures += test_loop();
+    failures += test_channel();
+    failures += test_scene_all();
+    failures += test_fifo();
+
+    if (failures > 0) {
+        fprintf(stderr, "%d test(s) FAILED\n", failures);
+        return 1;
+    }
+    printf("All tests completed successfully.\n");
+    return 0;
+}