fix(scanner): normalize Epson collection separators

backend/src/routes/scannerInboxGateway.ts

@@ -26,7 +26,9 @@ export default async function scannerInboxGateway(server: FastifyInstance, optio
 
     const handle = async (req: FastifyRequest, reply: any) => {
         const identity = identities.get(req)!
-        const filename = (req.params as { "*"?: string })["*"] || ""
+        // Epson appends its own separator even when the configured inbox URL ends in '/'.
+        // Remove only extra separators at the collection boundary, not within filenames.
+        const filename = ((req.params as { "*"?: string })["*"] || "").replace(/^\/+/, "")
         if (filename && (filename.length > 200 || filename.startsWith(".") || /[\\/\u0000-\u001f\u007f]/.test(filename))) {
             throw scannerError(400, "Unterordner und ungültige Dateinamen werden nicht unterstützt.")
         }