feat(core): rename string and stream functions for clarity

- Rename `cstring_push` to `cstring_append_ch` and `cstring_push_cstr` to `cstring_append_cstr` for consistent naming with new `cstring_append` function
- Update all callers in lexer and tests to use new function names
- Rename stream `destroy` method to `drop` for consistency with resource management conventions
- Fix potential overflow in string capacity calculation by adjusting growth logic

runtime/libcore/include/core_str.h

@@ -72,13 +72,14 @@ static inline void cstring_free(cstring_t *str) {
  * @param data 要追加的 C 字符串指针
  * @param len 要追加的 C 字符串长度
  */
-static inline void cstring_push_cstr(cstring_t *str, const char *data,
-                                     usize len) {
+static inline void cstring_append_cstr(cstring_t *str, const char *data,
+                                       usize len) {
     if (str == null || data == null || len == 0) {
         return;
     }
 
     if (str->cap == 0) {
+        // add '\0' to str
         str->size = 1;
     }
 
@@ -86,12 +87,13 @@ static inline void cstring_push_cstr(cstring_t *str, const char *data,
     if (str->size + len > str->cap) {
         usize new_cap = str->cap;
         while (new_cap < str->size + len) {
-            new_cap *= 2;
-            // FIXME write by AI 处理溢出情况
             if (new_cap == 0) {
                 new_cap = str->size + len;
                 break;
+            } else {
+                new_cap *= 2;
             }
+            // FIXME 处理溢出情况
         }
 
         char *new_data = (char *)smcc_realloc(str->data, new_cap);
@@ -106,14 +108,24 @@ static inline void cstring_push_cstr(cstring_t *str, const char *data,
     str->data[str->size - 1] = '\0'; // 保证 C 字符串兼容性
 }
 
+/**
+ * @brief 向动态字符串末尾追加另一个动态字符串
+ *
+ * @param str 目标动态字符串指针
+ * @param other 要追加的动态字符串指针
+ */
+static inline void cstring_append(cstring_t *str, const cstring_t *other) {
+    cstring_append_cstr(str, other->data, other->size - 1);
+}
+
 /**
  * @brief 向动态字符串末尾追加一个字符
  *
  * @param str 目标动态字符串指针
  * @param ch 要追加的字符
  */
-static inline void cstring_push(cstring_t *str, char ch) {
-    cstring_push_cstr(str, &ch, 1);
+static inline void cstring_append_ch(cstring_t *str, char ch) {
+    cstring_append_cstr(str, &ch, 1);
 }
 
 /**