chore: add increment/decrement operators and test suite to parser and tokenizer

Implement prefix and postfix ++/-- operators in the tokenizer (Inc/Dec token types) and parser (factor/unary functions) with correct pre/post semantics. Add increment_decrement_test.rc covering all four operator forms. Update Makefile to include the new test file in TESTS, add run-increment-decrement-test target, and fix .PHONY and TARGET dependency on dirs.

Makefile

@@ -24,13 +24,14 @@ TESTS = $(TEST_DIR)/feature_test.rc \
         $(TEST_DIR)/endless_loop_test.rc \
         $(TEST_DIR)/math_test.rc \
         $(TEST_DIR)/string_test.rc \
-        $(TEST_DIR)/string_manip_test.rc
+        $(TEST_DIR)/string_manip_test.rc \
+        $(TEST_DIR)/increment_decrement_test.rc
 
 EXAMPLES = $(EXAMPLE_DIR)/http_simple.rc \
            $(EXAMPLE_DIR)/http_persistent.rc \
            $(EXAMPLE_DIR)/http_multi.rc
 
-.PHONY: all clean test run-tests run-examples help dirs
+.PHONY: all clean test run-tests run-examples help
 
 all: dirs $(TARGET)
 
@@ -40,7 +41,7 @@ dirs:
 $(BUILD_DIR)/%.o: $(SRC_DIR)/%.c
 	$(CC) $(CFLAGS) -c $< -o $@
 
-$(TARGET): $(OBJECTS)
+$(TARGET): dirs $(OBJECTS)
 	$(CC) $(OBJECTS) -o $(TARGET) $(LDFLAGS)
 
 clean:
@@ -64,6 +65,9 @@ test: $(TARGET)
 	@echo "Running string manipulation tests..."
 	@$(TARGET) $(TEST_DIR)/string_manip_test.rc 2>&1 | grep -v "Error at token" || true
 	@echo ""
+	@echo "Running increment decrement tests..."
+	@$(TARGET) $(TEST_DIR)/increment_decrement_test.rc 2>&1 | grep -v "Error at token" || true
+	@echo ""
 	@echo "=== All Tests Completed ==="
 
 run-feature-test: $(TARGET)
@@ -81,6 +85,9 @@ run-string-test: $(TARGET)
 run-string-manip: $(TARGET)
 	$(TARGET) $(TEST_DIR)/string_manip_test.rc
 
+run-increment-decrement-test: $(TARGET)
+	$(TARGET) $(TEST_DIR)/increment_decrement_test.rc
+
 run-http-simple: $(TARGET)
 	$(TARGET) $(EXAMPLE_DIR)/http_simple.rc