fix(eims): a config error before signing must not block the whole system

settleFailure() treated any non-EimsApiException error as ambiguous
("might have reached MoR") and permanently blocked all further
filing until manually resolved. EimsConfigException (bad/missing
key, unparseable cert) is thrown by EimsSignerService before
EimsClientService.send()'s try/catch is even entered — by
construction it never reached the wire, so there is nothing
ambiguous about it.

This is exactly what happened live: a private-key parse failure
during the key/cert migration work reserved a counter, failed before
any HTTP call, and got treated as an unresolved in-flight submission
— blocking every other invoice from filing until someone manually
POSTs /eims/resolve.

Fix: EimsConfigException is now deterministic in settleFailure, same
treatment as a clean MoR rejection — both counters roll back, no
system-wide block, invoice marked FAILED (not UNKNOWN). Added a
CONFIG failure kind so the invoice's eimsLastError and the staff
alert both say plainly that the request never reached MoR, instead
of implying a MoR rejection.

apps/edr-freight-api/src/modules/eims/eims.errors.ts

@@ -10,7 +10,8 @@ export type EimsFailureKind =
   | "FORBIDDEN"
   | "RULE_VALIDATION"
   | "SERVER"
-  | "UNKNOWN";
+  | "UNKNOWN"
+  | "CONFIG";
 
 /** Raised when EIMS is disabled or its credential files are unusable. */
 export class EimsConfigException extends ServiceUnavailableException {