Document GITHUB_TOKEN for forum build in .env.example

Author: HumbleBee14

.env.example

@@ -7,9 +7,18 @@ PUBLIC_GA_MEASUREMENT_ID=
 # Giscus (GitHub Discussions comments). Get IDs from https://giscus.app
 # Repo: MLSysDev/mlsystems.dev, Category: Comments, Mapping: pathname.
 # Leaving these blank shows the "comments not configured" fallback.
+# The forum reuses PUBLIC_GISCUS_REPO_ID for inline per-thread commenting.
 PUBLIC_GISCUS_REPO_ID=
 PUBLIC_GISCUS_CATEGORY_ID=
 
+# Forum: read-only token used AT BUILD to pull GitHub Discussions into the forum.
+# Not PUBLIC_ — server/build only, never shipped to the client. A fine-grained or
+# classic PAT with read-only access to this repo's Discussions is enough (public
+# repo needs no scopes / `public_repo`). Leave blank to render an empty forum.
+# Set the same value in the Cloudflare Pages build env (and Functions env).
+# Locally you can reuse the gh CLI token:  GITHUB_TOKEN=$(gh auth token) npm run build
+GITHUB_TOKEN=
+
 # Show the "Designed share card" opt-in under a cover in /write. Only "true"
 # enables it; anything else (or unset) is treated as off. Opted-in posts render
 # a per-post OG card at build, so leave off unless you want that cost.