test(e2e): teach the eTrade mock to answer "no record"

Every TIN resolved to the same canned company, so the premise of both manual
routes — eTrade holds nothing — could not be reached at all, and neither could
the dead end an ordinary company hits on a TIN with no trade licence.

The answer now follows the TIN's leading digit, so a spec picks its outcome by
picking its number and no per-spec stubbing is needed: 9… returns a
registration with no businesses (the co-operative / investor case, where the
API's resolveCompanyData finds no licence), 8… 404s the registration lookup
entirely, anything else behaves as before.

e2e/freight/etrade-mock/server.js

@@ -9,10 +9,30 @@
 // TLS_CERT_PATH/TLS_KEY_PATH before starting this — nothing shaped like a
 // key/cert is committed here.
 //
-// Every TIN resolves to the same canned company — these specs don't care
+// A TIN resolves to the same canned company whatever its digits, EXCEPT for
-// about per-TIN business logic, only that the lookup succeeds so the rest
+// the two failure shapes the onboarding specs need — chosen by the TIN's
-// of the company-info form (name, address, manager) auto-fills instead of
+// leading digit so a spec picks its outcome by picking its number, with no
-// staying gated behind a "No matching business record" alert.
+// per-spec stubbing and no state in this process:
+//
+//   1xxxxxxxxx (default)  registration + one business licence  → "Verified with eTrade"
+//   9xxxxxxxxx            registration, but `Businesses: []`   → the API's resolveCompanyData
+//                                                                returns businessInfo: null,
+//                                                                so /fetch-etrade-info 400s
+//                                                                with "couldn't find a
+//                                                                business license for this
+//                                                                TIN". This is the real
+//                                                                co-operative / foreign-
+//                                                                investor case: the TIN is
+//                                                                registered, the trade
+//                                                                licence is not.
+//   8xxxxxxxxx            404 on the registration lookup       → getCompanyInfoByTin throws,
+//                                                                same 400 to the portal by a
+//                                                                different route (eTrade knows
+//                                                                nothing about this TIN at all).
+//
+// Both failures reach the portal as a 400, which ETradeInfo renders as its
+// `notFound` branch: a red dead end for an ordinary company, and the blue
+// "that's expected" alert for one that types its registration.
 const https = require("node:https");
 const fs = require("node:fs");
 
@@ -25,6 +45,11 @@ const options = {
   ),
 };
 
+/** No trade licence on file for this TIN (a co-operative, a foreign investor). */
+const TIN_WITHOUT_LICENCE = "9";
+/** eTrade holds no registration whatsoever for this TIN. */
+const TIN_UNKNOWN = "8";
+
 function companyInfo(tin) {
   return {
     Tin: tin,
@@ -101,8 +126,21 @@ const server = https.createServer(options, (req, res) => {
     /^\/api\/Registration\/GetRegistrationInfoByTin\/([^/]+)\/en$/,
   );
   if (req.method === "GET" && regMatch) {
+    const tin = regMatch[1];
+
+    if (tin.startsWith(TIN_UNKNOWN)) {
+      res.writeHead(404).end();
+      return;
+    }
+
+    const info = companyInfo(tin);
+    // Registered, but holding no trade licence. The API reads `Businesses`
+    // rather than the HTTP status to decide this, so an empty array is the
+    // honest shape — not an error.
+    if (tin.startsWith(TIN_WITHOUT_LICENCE)) info.Businesses = [];
+
     res.writeHead(200, { "content-type": "application/json" });
-    res.end(JSON.stringify(companyInfo(regMatch[1])));
+    res.end(JSON.stringify(info));
     return;
   }