refactor(lexer): 重构词法分析器头文件结构并优化缓冲区管理

移除了旧的lexer_stream.c实现，引入新的环形缓冲区机制来替代原有的
动态数组缓冲区。更新了词法分析器的核心数据结构，修改了token获取
相关函数的实现以支持新的缓冲区管理方式。

BREAKING CHANGE: 移除了scc_lexer_stream_t相关的API，替换为基于
环形缓冲区的新接口scc_lexer_to_ring和相关函数。

feat(lexer_token): 添加词法分析结果内存泄漏警告注释

docs: 移除预处理器模块的测试文件和相关配置

libs/lexer/src/lexer.c

@@ -1,5 +1,6 @@
-#include <lexer.h>
+#include "scc_lexer.h"
 #include <lexer_log.h>
+#include <scc_lexer.h>
 
 static const struct {
     const char *name;
@@ -41,7 +42,8 @@ static int keyword_cmp(const char *name, int len) {
 }
 
 void scc_lexer_init(scc_lexer_t *lexer, scc_sstream_ring_t *stream_ref) {
-    lexer->stream_ref = *stream_ref;
+    lexer->stream_ref = stream_ref;
+    lexer->ring_ref_count = 0;
     lexer->jump_macro = false;
 }
 
@@ -68,7 +70,7 @@ static inline cbool is_hex_digit(int ch) {
 /* 从环形缓冲区预览一个字符（带EOF检测） */
 static inline cbool peek_char(scc_lexer_t *lexer, scc_sstream_char_t *out) {
     cbool ok;
-    scc_ring_peek(lexer->stream_ref, *out, ok);
+    scc_ring_peek(*lexer->stream_ref, *out, ok);
     return ok;
 }
 
@@ -76,7 +78,7 @@ static inline cbool peek_char(scc_lexer_t *lexer, scc_sstream_char_t *out) {
 static inline cbool next_char(scc_lexer_t *lexer, scc_cstring_t *lexeme,
                               scc_sstream_char_t *out) {
     cbool ok;
-    scc_ring_next(lexer->stream_ref, *out, ok);
+    scc_ring_next(*lexer->stream_ref, *out, ok);
     if (!ok)
         return false;
     scc_cstring_append_ch(lexeme, out->character);
@@ -132,7 +134,7 @@ void scc_lexer_get_token(scc_lexer_t *lexer, scc_lexer_tok_t *token) {
             next_char(lexer, &lex, &cur); // 消费 '/'
             while (peek_char(lexer, &cur) && !is_newline(cur.character)) {
                 next_char(lexer, &lex, &cur);
-                scc_ring_consume(lexer->stream_ref);
+                scc_ring_consume(*lexer->stream_ref);
             }
             // 注释结束，不包含换行符（换行符单独成token）
         } else if (next.character == '*') {
@@ -150,7 +152,7 @@ void scc_lexer_get_token(scc_lexer_t *lexer, scc_lexer_tok_t *token) {
                     next_char(lexer, &lex, &cur); // 消费 '/'
                     break;
                 }
-                scc_ring_consume(lexer->stream_ref);
+                scc_ring_consume(*lexer->stream_ref);
             }
         } else {
             // 只是除号 /
@@ -161,7 +163,7 @@ void scc_lexer_get_token(scc_lexer_t *lexer, scc_lexer_tok_t *token) {
         token->type = SCC_TOK_IDENT; // 暂定
         while (peek_char(lexer, &cur) && is_identifier_part(cur.character)) {
             next_char(lexer, &lex, &cur);
-            scc_ring_consume(lexer->stream_ref);
+            scc_ring_consume(*lexer->stream_ref);
         }
         // 检查是否为关键字
         int idx = keyword_cmp(scc_cstring_as_cstr(&lex), scc_cstring_len(&lex));
@@ -241,7 +243,7 @@ void scc_lexer_get_token(scc_lexer_t *lexer, scc_lexer_tok_t *token) {
             } else {
                 next_char(lexer, &lex, &cur);
             }
-            scc_ring_consume(lexer->stream_ref);
+            scc_ring_consume(*lexer->stream_ref);
         }
     } else {
         scc_sstream_char_t next = {0};
@@ -447,7 +449,7 @@ void scc_lexer_get_token(scc_lexer_t *lexer, scc_lexer_tok_t *token) {
     }
 
     // 设置token
-    scc_ring_consume(lexer->stream_ref);
+    scc_ring_consume(*lexer->stream_ref);
     token->type = token->type; // 上面已设
     token->loc = start_loc;
     token->lexeme = lex; // 转移所有权
@@ -469,3 +471,42 @@ void scc_lexer_get_valid_token(scc_lexer_t *lexer, scc_lexer_tok_t *token) {
     } while (subtype == SCC_TOK_SUBTYPE_EMPTYSPACE ||
              subtype == SCC_TOK_SUBTYPE_COMMENT);
 }
+
+static int fill_token(scc_lexer_tok_t *out, void *userdata) {
+    scc_lexer_t *lexer = userdata;
+    scc_lexer_get_token(lexer, out);
+    return 0;
+}
+
+static int fill_valid_token(scc_lexer_tok_t *out, void *userdata) {
+    scc_lexer_t *lexer = userdata;
+    scc_lexer_get_valid_token(lexer, out);
+    return 0;
+}
+
+scc_lexer_tok_ring_t *scc_lexer_to_ring(scc_lexer_t *lexer, int ring_size,
+                                        cbool need_comment) {
+    scc_ring_init(lexer->ring, ring_size,
+                  need_comment ? fill_token : fill_valid_token, lexer);
+    lexer->ring_ref_count++;
+    return &lexer->ring;
+}
+
+void scc_lexer_drop_ring(scc_lexer_tok_ring_t *ring_ref) {
+    scc_lexer_t *lexer = ring_ref->userdata;
+    if (lexer->ring_ref_count > 0) {
+        lexer->ring_ref_count--;
+    } else {
+        LOG_WARN("double drop sstream ring");
+    }
+}
+
+void scc_lexer_drop(scc_lexer_t *lexer) {
+    Assert(lexer != null);
+    if (lexer->ring_ref_count) {
+        LOG_FATAL("drop sstream must be drop ring before ref [%d]",
+                  lexer->ring_ref_count);
+    }
+    scc_ring_free(lexer->ring);
+    scc_sstream_drop_ring(lexer->stream_ref);
+}