Add Makefile with build and test targets

Makefile

@@ -0,0 +1,56 @@
+SHELL  := /bin/bash
+CC     := cc
+CFLAGS := -Wall -O2
+TARGET := fa2json
+SRCS   := fs-watcher.c json-writer.c
+
+.PHONY: all test clean
+
+all: $(TARGET)
+
+$(TARGET): $(SRCS)
+	$(CC) $(CFLAGS) -o $@ $^
+
+# Requires root (fanotify FID + mount needs CAP_SYS_ADMIN).
+# Loop device and mount are cleaned up automatically on exit.
+# If the test aborts unexpectedly, check: losetup -l and /proc/mounts
+test: $(TARGET)
+	@set -euo pipefail; \
+	IMG=""; MNTDIR=""; LOOPDEV=""; FA2JSON_PID=""; \
+	cleanup() { \
+		[ -n "$$FA2JSON_PID" ] && { kill "$$FA2JSON_PID" 2>/dev/null; wait "$$FA2JSON_PID" 2>/dev/null || true; }; \
+		[ -n "$$MNTDIR" ]      && umount "$$MNTDIR"    2>/dev/null || true; \
+		[ -n "$$LOOPDEV" ]     && losetup -d "$$LOOPDEV" 2>/dev/null || true; \
+		[ -n "$$IMG" ]         && rm -f "$$IMG"; \
+		[ -n "$$MNTDIR" ]      && rmdir "$$MNTDIR"     2>/dev/null || true; \
+	}; \
+	trap cleanup EXIT; \
+	IMG=$$(mktemp /tmp/fa2json-test-XXXXXX.img); \
+	MNTDIR=$$(mktemp -d /tmp/fa2json-mnt-XXXXXX); \
+	echo "--- Creating 10M ext4 image ---"; \
+	dd if=/dev/zero of="$$IMG" bs=1M count=10 status=none; \
+	mkfs.ext4 -q "$$IMG"; \
+	LOOPDEV=$$(losetup --find --show "$$IMG"); \
+	mount "$$LOOPDEV" "$$MNTDIR"; \
+	echo "--- Starting fa2json on $$MNTDIR ---"; \
+	./$(TARGET) "$$MNTDIR" & FA2JSON_PID=$$!; \
+	sleep 0.3; \
+	echo "--- Filesystem operations ---"; \
+	mkdir "$$MNTDIR/dir_a"; \
+	touch "$$MNTDIR/file_a.txt"; \
+	echo "content" >> "$$MNTDIR/file_a.txt"; \
+	mkdir "$$MNTDIR/dir_b"; \
+	touch "$$MNTDIR/dir_b/nested.txt"; \
+	mv "$$MNTDIR/file_a.txt" "$$MNTDIR/file_b.txt"; \
+	mv "$$MNTDIR/dir_b" "$$MNTDIR/dir_a/dir_b_moved"; \
+	chmod 600 "$$MNTDIR/file_b.txt"; \
+	touch -m "$$MNTDIR/file_b.txt"; \
+	chmod 755 "$$MNTDIR/dir_a"; \
+	rm "$$MNTDIR/file_b.txt"; \
+	rm "$$MNTDIR/dir_a/dir_b_moved/nested.txt"; \
+	rm -rf "$$MNTDIR/dir_a"; \
+	sleep 0.3; \
+	echo "--- Done ---"
+
+clean:
+	rm -f $(TARGET)