fix(settings): rename remark model 'Other' to 'External Proxy' (#5265)

The 'o' remark block is sourced from an external proxy's remark, but the
label 'Other' gave no hint where to set it. Rename the display label to
'External Proxy' to match the inbound form section; the stored 'o' key is
unchanged so existing remarkModel values stay compatible.

frontend/src/pages/settings/SubscriptionGeneralTab.tsx

@@ -8,7 +8,7 @@ import { useMediaQuery } from '@/hooks/useMediaQuery';
 import { catTabLabel } from './catTabLabel';
 import { sanitizePath, normalizePath } from './uriPath';
 
-const REMARK_MODELS: Record<string, string> = { i: 'Inbound', e: 'Email', o: 'Other' };
+const REMARK_MODELS: Record<string, string> = { i: 'Inbound', e: 'Email', o: 'External Proxy' };
 const REMARK_SAMPLES: Record<string, string> = { i: 'Germany', e: 'john', o: 'Relay' };
 const REMARK_SEPARATORS = [' ', '-', '_', '@', ':', '~', '|', ',', '.', '/'];