fix(website): count only OpenScreen release assets on github.com as downloads

Author: EtienneLescot

website/src/lib/download-target.test.ts

@@ -163,4 +163,6 @@ test("a download click names the asset kind and the release, and other links are
 	assert.equal(downloadClick(STORE_INSTALLER_URL)?.kind, "store");
 	assert.equal(downloadClick("https://github.com/getopenscreen/openscreen/releases/latest"), null);
 	assert.equal(downloadClick(STORE_URL), null);
+	assert.equal(downloadClick("https://github.com/someone/else/releases/download/v1/x.dmg"), null);
+	assert.equal(downloadClick(`https://example.com/?next=${base}/Openscreen-mac-arm64.dmg`), null);
 });

website/src/lib/download-target.ts

@@ -117,10 +117,19 @@ export type DownloadClick = {
 	file: string | null;
 };
 
-/** What a link downloads, for the analytics event, or null when it downloads nothing. */
+const RELEASE_ASSET_PATH = /^\/getopenscreen\/openscreen\/releases\/download\/([^/]+)\/([^/]+)$/;
+
+/** What a link downloads, for the analytics event, or null when it downloads nothing: an
+ *  OpenScreen release asset on github.com, or the Store installer. */
 export function downloadClick(href: string): DownloadClick | null {
 	if (href.startsWith(STORE_INSTALLER_URL)) return { kind: "store", version: null, file: null };
-	const match = /\/releases\/download\/([^/]+)\/([^/?#]+)/.exec(href);
+	let url: URL;
+	try {
+		url = new URL(href);
+	} catch {
+		return null;
+	}
+	const match = url.hostname === "github.com" ? RELEASE_ASSET_PATH.exec(url.pathname) : null;
 	if (!match) return null;
 	const file = decodeURIComponent(match[2]);
 	const kind = (Object.keys(ASSET_PATTERNS) as AssetKind[]).find((k) =>