Refactor transit_api into a repo/routes module split

Split the 5,441-line index.js into an 86-line bootstrap, thin domain
route modules, shared lib/ helpers, and a repo/ layer that isolates the
DEV_MOCK branches (repo/*.mock.js). Repo methods return {statusCode, body};
routes are one-line wrappers. Pin search_path to "transit.bus" and
document the /bus/ prefix with legacy root aliases (Deprecation header).

Parity verified: 57/57 byte-identical on the stub differential harness
plus 24/24 live read-only responses vs the original against real
PostgreSQL. The only intentional behavior change: mock reorder/delete
bus-line endpoints no longer require a live DB (previously 500 in
DEV_MOCK=1 without PG). DEV_MOCK gate and node --check clean.

transit_api/middleware.js

@@ -3,10 +3,37 @@ require('dotenv').config();
 
 const JWT_SECRET = process.env.JWT_SECRET;
 
+const ERROR_LOG_API_URL =
+  process.env.ERROR_LOG_API_URL ||
+  "https://error.xtransit.testinstance.nl/error_log";
+
+function log(level, message, meta = {}) {
+  const timestamp = new Date().toISOString();
+  console.log(JSON.stringify({ timestamp, level, service: "transit_api", message, ...meta }));
+}
+
+async function reportError({ partofservice, error }) {
+  try {
+    await fetch(ERROR_LOG_API_URL, {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+        "x-internal-api-key": process.env.INTERNAL_API_KEY || "",
+      },
+      body: JSON.stringify({
+        service: "transit_api",
+        partofservice,
+        error,
+      }),
+    });
+  } catch (_) {}
+}
+
 // Middleware to verify JWT token
 const authMiddleware = (req, res, next) => {
   const auth = req.headers.authorization;
   if (!auth || !auth.startsWith('Bearer ')) {
+    log("warn", "Missing or invalid Authorization header", { path: req.originalUrl });
     return res.status(401).json({ error: 'missing_token' });
   }
 
@@ -16,8 +43,23 @@ const authMiddleware = (req, res, next) => {
     req.user = payload;
     next();
   } catch (err) {
+    log("error", "JWT verification failed", { error: err.message, path: req.originalUrl });
+    void reportError({
+      partofservice: `authMiddleware ${req.method} ${req.originalUrl}`,
+      error: err.stack || err.message,
+    });
     return res.status(401).json({ error: 'invalid_token' });
   }
 };
 
-module.exports = { authMiddleware };
+
+// Middleware to enforce admin role
+const adminMiddleware = (req, res, next) => {
+  if (!req.user || !req.user.isAdmin) {
+    return res.status(403).json({ error: "forbidden" });
+  }
+
+  next();
+};
+
+module.exports = { authMiddleware, adminMiddleware };