feat(lex_parser): 初始化词法解析器模块

新增词法解析器库 `smcc_lex_parser`，包含基础的词法规则解析功能：
- 支持字符、字符串、数字、标识符的解析
- 支持跳过注释、空白符、行尾等辅助函数
- 提供对应的单元测试用例，覆盖各类合法与非法输入情况

该模块依赖 `libcore`，并被 `smcc_lex` 模块引用以支持更上层的词法分析逻辑。

libs/lex_parser/tests/test_skip_block_comment.c

@@ -0,0 +1,50 @@
+// test_skip_block_comment.c
+#include <lex_parser.h>
+#include <utest/acutest.h>
+
+void check_skip_block_comment(const char *str, const char *expect_remaining) {
+    log_set_level(&__default_logger_root, 0);
+    core_pos_t pos = core_pos_init();
+    core_mem_stream_t mem_stream;
+    core_stream_t *stream =
+        core_mem_stream_init(&mem_stream, str, smcc_strlen(str), false);
+
+    lex_parse_skip_block_comment(stream, &pos);
+
+    // Check remaining content
+    char buffer[256] = {0};
+    int i = 0;
+    int ch;
+    while ((ch = core_stream_next_char(stream)) != core_stream_eof && i < 255) {
+        buffer[i++] = (char)ch;
+    }
+
+    if (expect_remaining) {
+        TEST_CHECK(strcmp(buffer, expect_remaining) == 0);
+    }
+}
+
+void test_simple_block_comment(void) {
+    TEST_CASE("simple block comments");
+    check_skip_block_comment("/* comment */", "");
+    check_skip_block_comment("/* comment */ int x;", " int x;");
+}
+
+void test_multiline_block_comment(void) {
+    TEST_CASE("multiline block comments");
+    check_skip_block_comment("/* line1\nline2 */", "");
+    check_skip_block_comment("/* line1\nline2 */ int x;", " int x;");
+}
+
+void test_nested_asterisk_block_comment(void) {
+    TEST_CASE("nested asterisk block comments");
+    check_skip_block_comment("/* *** */", "");
+    check_skip_block_comment("/* *** */ int x;", " int x;");
+}
+
+TEST_LIST = {
+    {"test_simple_block_comment", test_simple_block_comment},
+    {"test_multiline_block_comment", test_multiline_block_comment},
+    {"test_nested_asterisk_block_comment", test_nested_asterisk_block_comment},
+    {NULL, NULL},
+};