chore: add slide template section to speaker participation page

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: hpcslag

content/en/participate/speaker-participation.md

@@ -36,6 +36,12 @@ This page summarizes what COSCUP speakers should confirm before and during the e
 
 The livestream and recording aspect ratio is 16:9 for every classroom, with a resolution of 1920 x 1080.
 
+## Slide Template
+
+There is no required slide style — feel free to use your own. If you prefer a unified look, you are welcome to download and use the official slide template: <https://s.coscup.org/26slide>
+
+The slide template is released under CC BY 4.0.
+
 ## Slide Content Notes
 
 - Do not use music with copyright concerns.

content/zh/participate/speaker-participation.md

@@ -36,6 +36,12 @@ description: "COSCUP 2026 講者指南：事前確認、設備、投影片格式
 
 直播和錄影時的比例無論哪間教室都是 16:9，解析度為 1920 x 1080。
 
+## 簡報模板
+
+簡報樣式不拘，您可以自由使用自己習慣的簡報風格。若偏好使用統一樣式，可自行下載大會提供的簡報模板使用：<https://s.coscup.org/26slide>
+
+模板簡報以 CC BY 4.0 釋出。
+
 ## 簡報內容注意事項
 
 - 請勿使用有版權疑慮的音樂。