feat(lex_parser): rename functions and update header guard prefix

- Change header guard from `__SMCC_LEX_PARSER_H__` to `__SCC_LEX_PARSER_H__`
- Prefix all lexer functions with `scc_` (e.g., `lex_parse_char` → `scc_lex_parse_char`)
- Add new helper function `scc_lex_parse_is_identifier_header`
- Update references in source and test files to use new function names
- Replace `core_stream_eof` with `scc_stream_eof` for consistency

libs/lexer/include/lexer.h

@@ -9,11 +9,11 @@
 #include "lexer_token.h"
 #include <libcore.h>
 
-typedef struct lexer_token {
+typedef struct scc_lexer_token {
     scc_tok_type_t type;
     scc_cvalue_t value;
     scc_pos_t loc;
-} lexer_tok_t;
+} scc_lexer_tok_t;
 
 /**
  * @brief 词法分析器核心结构体
@@ -39,7 +39,7 @@ void scc_lexer_init(scc_lexer_t *lexer, scc_probe_stream_t *stream);
  *
  * 此函数会返回所有类型的token，包括空白符等无效token
  */
-void scc_lexer_get_token(scc_lexer_t *lexer, lexer_tok_t *token);
+void scc_lexer_get_token(scc_lexer_t *lexer, scc_lexer_tok_t *token);
 
 /**
  * @brief 获取有效token
@@ -48,6 +48,6 @@ void scc_lexer_get_token(scc_lexer_t *lexer, lexer_tok_t *token);
  *
  * 此函数会自动跳过空白符等无效token，返回对语法分析有意义的token
  */
-void scc_lexer_get_valid_token(scc_lexer_t *lexer, lexer_tok_t *token);
+void scc_lexer_get_valid_token(scc_lexer_t *lexer, scc_lexer_tok_t *token);
 
 #endif /* __SCC_LEXER_H__ */