refactor: centralize enum validation for unit and renewal type

SubMind.py

@@ -255,6 +255,8 @@ EDITABLE_SUB_FIELDS = {
 MAX_NAME_LEN = 128
 MAX_CATEGORY_LEN = 64
 MAX_NOTES_LEN = 1000
+VALID_FREQ_UNITS = {'day', 'week', 'month', 'year'}
+VALID_RENEWAL_TYPES = {'auto', 'manual'}
 
 
 def _build_category_callback_data(category_id: int) -> str:
@@ -679,7 +681,11 @@ async def add_next_due_received(update: Update, context: CallbackContext):
 async def add_freq_unit_received(update: Update, context: CallbackContext):
     query = update.callback_query
     await query.answer()
-    context.user_data['new_sub_data']['unit'] = query.data.split('_')[2]
+    unit = query.data.split('_')[2]
+    if unit not in VALID_FREQ_UNITS:
+        await query.edit_message_text("错误：无效的周期单位，请重试。")
+        return ConversationHandler.END
+    context.user_data['new_sub_data']['unit'] = unit
     await query.edit_message_text("第七步：请输入周期的*数量*（例如：每3个月，输入 3）", parse_mode='Markdown')
     return ADD_FREQ_VALUE
 
@@ -705,7 +711,11 @@ async def add_freq_value_received(update: Update, context: CallbackContext):
 async def add_renewal_type_received(update: Update, context: CallbackContext):
     query = update.callback_query
     await query.answer()
-    context.user_data['new_sub_data']['renewal_type'] = query.data.split('_')[1]
+    renewal_type = query.data.split('_')[1]
+    if renewal_type not in VALID_RENEWAL_TYPES:
+        await query.edit_message_text("错误：无效的续费类型，请重试。")
+        return ConversationHandler.END
+    context.user_data['new_sub_data']['renewal_type'] = renewal_type
     await query.edit_message_text("最后一步（可选）：需要添加备注吗？\n（如：共享账号、用途等。不需要请 /skip）")
     return ADD_NOTES
 
@@ -1083,7 +1093,11 @@ async def edit_field_selected(update: Update, context: CallbackContext):
 async def edit_freq_unit_received(update: Update, context: CallbackContext):
     query = update.callback_query
     await query.answer()
-    context.user_data['new_freq_unit'] = query.data.split('_')[2]
+    unit = query.data.split('_')[2]
+    if unit not in VALID_FREQ_UNITS:
+        await query.edit_message_text("错误：无效的周期单位，请重试。")
+        return ConversationHandler.END
+    context.user_data['new_freq_unit'] = unit
     await query.edit_message_text("好的，现在请输入新的周期*数量*。", parse_mode='MarkdownV2')
     return EDIT_FREQ_VALUE
 
@@ -1188,7 +1202,7 @@ async def edit_new_value_received(update: Update, context: CallbackContext):
         else:
             new_value = parsed
     elif field == 'renewal_type':
-        if str(new_value) not in ('auto', 'manual'):
+        if str(new_value) not in VALID_RENEWAL_TYPES:
             if message_to_reply:
                 await message_to_reply.reply_text("续费方式只能为 auto 或 manual。")
             validation_failed = True