website: add a GitHub social button to the site's header

apps/website/src/github-utils.ts

@@ -0,0 +1,15 @@
+const API_URL = "https://api.github.com/repos/TriliumNext/Trilium";
+
+/** Returns the number of stargazers of the Trilium's GitHub repository. */
+export async function getRepoStargazersCount() {
+	const response = await fetch(API_URL);
+	
+	if (response.ok) {
+		const details = await response.json();
+		if ("stargazers_count" in details) {
+			return details["stargazers_count"];
+		}
+	}
+
+	return 31862; // The count as of 2025-10-03
+}