fix(inbounds): allow negative subSortIndex for subscription order (#6465)

* fix(inbounds): allow negative subSortIndex for subscription order

Preserve explicitly set negative indices so primary inbounds can sort
ahead of the default without renumbering peers; keep 0/omitted → 1.

* fix(inbounds): gofumpt model.go and trim subSortIndex comments

---------

Co-authored-by: mrchatam <287639636+mrchatam@users.noreply.github.com>

frontend/src/pages/inbounds/form/InboundFormModal.tsx

@@ -697,7 +697,7 @@ export default function InboundFormModal({
           t('pages.inbounds.form.subSortIndexHelp'),
         )}
       >
-        <InputNumber min={1} />
+        <InputNumber />
       </FormField>
 
       {protocol === Protocols.VLESS && (

frontend/src/pages/inbounds/list/InboundList.tsx

@@ -119,7 +119,7 @@ export default function InboundList({
   );
 
   const hasAnySubSortIndex = useMemo(
-    () => dbInbounds.some((i) => (i.subSortIndex ?? 1) > 1),
+    () => dbInbounds.some((i) => (i.subSortIndex ?? 1) !== 1),
     [dbInbounds],
   );