feat: list plugin engine ranges for the mobile app

src/backend/database/routes/plugins.ts

@@ -244,7 +244,9 @@ export async function listPreLoginPlugins(): Promise<
  *       `assetVersion` is its cache key, `css` says a stylesheet sits beside
  *       it, and `locales` lists the languages it ships ("en" and xx_YY).
  *       `dependencies` and `optionalDependencies` let the loader activate
- *       frontends in the same order the server does.
+ *       frontends in the same order the server does. `engine` holds the
+ *       manifest's `api` and `termix` ranges, so other clients (the mobile
+ *       app) can tell whether they understand the plugin.
  *
  *       On a desktop linked to a server, `runsOnServer` marks plugins that
  *       only run on that server and stay off here on purpose, and, for
@@ -303,6 +305,7 @@ router.get("/", authenticateJWT, async (req: Request, res: Response) => {
         let features: string[] = [];
         let docs: string | undefined;
         let env: PluginEnvVar[] = [];
+        const engine: { api?: string; termix?: string } = {};
         let desktopMode: unknown = loaded
           ? resolvePluginDesktopMode(loaded.manifest)
           : undefined;
@@ -322,7 +325,14 @@ router.get("/", authenticateJWT, async (req: Request, res: Response) => {
             optionalDependencies?: Record<string, string>;
             desktop?: unknown;
             runtime?: unknown;
+            engine?: { api?: unknown; termix?: unknown };
           };
+          if (typeof manifest?.engine?.api === "string") {
+            engine.api = manifest.engine.api;
+          }
+          if (typeof manifest?.engine?.termix === "string") {
+            engine.termix = manifest.engine.termix;
+          }
           desktopMode = loaded
             ? resolvePluginDesktopMode(loaded.manifest)
             : (manifest?.desktop ??
@@ -365,6 +375,7 @@ router.get("/", authenticateJWT, async (req: Request, res: Response) => {
               ? "safe-mode"
               : (loaded?.state ?? record.state),
           runsOnServer: linked && desktopMode === "server",
+          engine,
           contributes,
           icon,
           dependencies,