Switched Giscus mapping from 'pathname' to 'og:title' with strict=1.
Discussions are now titled after the readable page title (e.g.
'Chart Examples | Tibber Prices Integration') instead of the URL path,
making them immediately identifiable in the GitHub Discussions list.
Added a small hint above every comment box pointing users to open
a dedicated Discussion on GitHub for new questions/ideas, so
page-specific comments don't accumulate unrelated threads.
Note: Existing Discussion #94 (pathname-mapped) will no longer appear
on chart-examples — a new og:title-mapped discussion will be created
on the next comment. #94 remains visible on GitHub.
Impact: Maintainer can identify discussion origin at a glance.
Users are guided toward proper Discussion threads for new topics.
