feat(cmakev2): Added conditional_component example for cmakev2

This commit adds a new example at
examples/build_system/cmakev2/features/conditional_components to
demonstrate the cmakev2 ability to conditionally include components in
the build based on Kconfig options.

examples/build_system/cmakev2/features/conditional_component/main/CMakeLists.txt

@@ -0,0 +1,21 @@
+# This component provides the main function and conditionally
+# includes logging_util and math_util based on the Kconfig options.
+
+# Provide the main component as a static library
+add_library(${COMPONENT_TARGET} STATIC main.c)
+
+if(CONFIG_EXAMPLE_ENABLE_LOGGING)
+    idf_component_include(logging_util)
+    target_link_libraries(${COMPONENT_TARGET} PRIVATE idf::logging_util)
+    idf_msg("Conditional component 'logging_util' is ENABLED")
+else()
+    idf_msg("Conditional component 'logging_util' is DISABLED")
+endif()
+
+if(CONFIG_EXAMPLE_ENABLE_MATH)
+    idf_component_include(math_util)
+    target_link_libraries(${COMPONENT_TARGET} PRIVATE idf::math_util)
+    idf_msg("Conditional component 'math_util' is ENABLED")
+else()
+    idf_msg("Conditional component 'math_util' is DISABLED")
+endif()

examples/build_system/cmakev2/features/conditional_component/main/Kconfig.projbuild

@@ -0,0 +1,17 @@
+menu "Conditional Component Example Configuration"
+
+    config EXAMPLE_ENABLE_LOGGING
+        bool "Enable Logging Utility Component"
+        default y
+        help
+            Enable the logging_util component to demonstrate conditional
+            component inclusion in Build System v2.
+
+    config EXAMPLE_ENABLE_MATH
+        bool "Enable Math Utility Component"
+        default y
+        help
+            Enable the math_util component to demonstrate conditional
+            component inclusion in Build System v2.
+
+endmenu

examples/build_system/cmakev2/features/conditional_component/main/main.c

@@ -0,0 +1,49 @@
+/*
+ * SPDX-FileCopyrightText: 2026 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include "sdkconfig.h"
+
+#ifdef CONFIG_EXAMPLE_ENABLE_LOGGING
+#include "logging_util.h"
+#endif
+
+#ifdef CONFIG_EXAMPLE_ENABLE_MATH
+#include "math_util.h"
+#endif
+
+void app_main(void)
+{
+    printf("Conditional Component Example\n");
+    printf("==============================\n\n");
+
+    printf("This example demonstrates Build System v2's idf_component_include()\n");
+    printf("function for conditional component inclusion.\n\n");
+
+#ifdef CONFIG_EXAMPLE_ENABLE_LOGGING
+    printf("Logging component is ENABLED\n");
+    log_info("This is an info message from logging_util");
+    log_warn("This is a warning message from logging_util");
+#else
+    printf("Logging component is DISABLED\n");
+#endif
+
+    printf("\n");
+
+#ifdef CONFIG_EXAMPLE_ENABLE_MATH
+    printf("Math component is ENABLED\n");
+    int a = 10, b = 5;
+    printf("  add(%d, %d) = %d\n", a, b, math_add(a, b));
+    printf("  subtract(%d, %d) = %d\n", a, b, math_subtract(a, b));
+    printf("  multiply(%d, %d) = %d\n", a, b, math_multiply(a, b));
+#else
+    printf("Math component is DISABLED\n");
+#endif
+
+    printf("\n");
+    printf("You can change the component configuration via menuconfig:\n");
+    printf("  idf.py menuconfig -> Conditional Component Example Configuration\n");
+}