Re-trigger Pages deploy after default branch set to main

Default branch is now main, so the github-pages environment protection
rule (default-branch-only) will allow this deployment.

https://claude.ai/code/session_016VgNBuYfmvW644AFuD5Uiq

Author: claude

scripts/build_graph.py

@@ -10,7 +10,7 @@
 
 用法：python3 scripts/build_graph.py  →  產出 docs/graph.html
 卡片有增減時重跑即可。CI（.github/workflows/pages.yml）會在 push 到 main
-時自動重跑並發佈到 GitHub Pages。
+（repo 預設分支）時自動重跑並發佈到 GitHub Pages。
 """
 import re, json, pathlib, html