feat: move fleets into a first-party plugin

src/backend/database/routes/fleet-dispatch.ts

@@ -0,0 +1,48 @@
+// Mounted at /fleets. Fleets ships as a first-party in-process plugin
+// (plugins/fleets) rather than a route file imported directly here, so this
+// module exists to keep /fleets/* working at its original path without
+// handing the plugin a reference to the shared app instance. The plugin
+// runtime registers its router via registerFleetsRouter when it activates,
+// and clears it on deactivate, so a disabled plugin falls back to the 404
+// below.
+//
+// Unlike /plugin-api, this dispatcher applies no auth of its own: it forwards
+// to exactly one first-party router (the Fleets plugin's own), and every
+// route in that router already applies authenticateJWT/requireDataAccess
+// itself, the same as every other router mounted alongside it here (/users,
+// /host, /snippets, ...). /plugin-api gates at the mount point because it
+// forwards to arbitrary third-party plugin code that cannot be assumed to
+// gate itself; that reasoning does not apply to a single first-party router
+// that already does.
+
+import type { Request, Response, NextFunction, Router } from "express";
+import { databaseLogger } from "../../utils/logger.js";
+
+let activeRouter: Router | null = null;
+
+export function registerFleetsRouter(router: Router): void {
+  activeRouter = router;
+  databaseLogger.info("Registered Fleets plugin router", {
+    operation: "fleets_dispatch_register",
+  });
+}
+
+export function unregisterFleetsRouter(): void {
+  if (!activeRouter) return;
+  activeRouter = null;
+  databaseLogger.info("Unregistered Fleets plugin router", {
+    operation: "fleets_dispatch_register",
+  });
+}
+
+export default function fleetsDispatch(
+  req: Request,
+  res: Response,
+  next: NextFunction,
+): void {
+  if (!activeRouter) {
+    res.status(404).json({ error: "Fleets is not available" });
+    return;
+  }
+  activeRouter(req, res, next);
+}