feat: replace browser login with imported Reddit sessions

extensions/reddit-session-exporter/session-export.js

@@ -0,0 +1,34 @@
+const REDDITBOT_SESSION_FILENAME = 'redditbot-session.json';
+
+function isRedditDomain(domain) {
+  const normalised = domain.toLowerCase().replace(/^\./, '');
+  return normalised === 'reddit.com' || normalised.endsWith('.reddit.com');
+}
+
+function toExportCookie(cookie) {
+  return {
+    name: cookie.name,
+    value: cookie.value,
+    domain: cookie.domain,
+    path: cookie.path,
+    expires: cookie.expirationDate,
+    httpOnly: cookie.httpOnly,
+    secure: cookie.secure,
+    sameSite: cookie.sameSite,
+  };
+}
+
+export function createSessionExportDownload(cookies, matrix) {
+  if (!matrix?.homeserver || !matrix?.accessToken || !matrix?.userId) {
+    throw new Error('Open Reddit Chat before exporting so Matrix credentials can be captured.');
+  }
+  const exportFile = {
+    cookies: cookies.filter((cookie) => isRedditDomain(cookie.domain)).map(toExportCookie),
+    matrix,
+  };
+
+  return {
+    filename: REDDITBOT_SESSION_FILENAME,
+    url: `data:application/json;charset=utf-8,${encodeURIComponent(JSON.stringify(exportFile))}`,
+  };
+}