About: name the webmail node and the mail server node

Settings > About shows which webmail node answered (NODE_NAME, else the
container hostname) and which inbuxa node it talks to: the address the
server's name resolves to from the webmail, named by its PTR record. The
server only tells administrators its node name, so the webmail works it
out itself. Fetched from /api/about/nodes on every visit, cached for a
minute server-side, for troubleshooting a cluster.

Fork-only: upstream ihasmail runs one webmail against one server.
4 new strings, translated in all 9 catalogues.

server/src/app.ts

@@ -44,6 +44,7 @@ import { imageProxyHandler } from "./imageproxy.js";
 import { SignInError, finish as finishSignIn, needsRefresh, oauthEnabled, refreshTokens, singleServer, start as startSignIn, type TokenSet } from "./oauth.js";
 import { icsProxyHandler } from "./icsproxy.js";
 import { staticHandler } from "./static.js";
+import { mailNode, webmailNode } from "./nodes.js";
 
 type Env = { Variables: { session: LiveSession } };
 
@@ -609,6 +610,12 @@ export function createApp(basePath = config.basePath): Hono<Env> {
     return c.json({ ok: true });
   });
 
+  /* ihasmail-inbuxa: which webmail node this is, and which mail node it talks to (nodes.ts). */
+  api.get("/about/nodes", requireSession, async (c) => {
+    const session = c.get("session");
+    return c.json({ webmail: webmailNode(), mailServer: await mailNode(upstreamFor(session.username)) });
+  });
+
   api.get("/auth/sessions", requireSession, (c) => {
     const session = c.get("session");
     return c.json({ current: session.id, sessions: sessions.listForUser(session.account) });