i18n(panel): migrate hardcoded panel strings to en-US and translate all locales

Surface ~400 hardcoded English labels, tooltips, placeholders, dt/divider
text, modal okText/cancelText, and Spin loading from the panel pages
(clients/groups/inbounds/nodes/settings/xray/sub/index) into
web/translation/en-US.json under existing pages.<page>.* namespaces, with
JSX swapped to t(...). Brand and protocol identifiers (TLS, MTU, SNI,
NordVPN, Cloudflare WARP, etc.) stay literal.

Sync all 12 non-English locales (ar-EG, es-ES, fa-IR, id-ID, ja-JP,
pt-BR, ru-RU, tr-TR, uk-UA, vi-VN, zh-CN, zh-TW) to match en-US's
structure and translate the 521 new key paths per locale. Every locale
file now has 1539 lines, mirroring en-US ordering.

Also remove a dead duplicate "info": "Info" key under pages.inbounds
that collided with the new pages.inbounds.info.* object.

Backend: bulk attach/detach errors in web/service/client.go now route
through logger.Warningf (so they appear under /panel/api/server/logs/)
instead of only living on the response payload.

frontend/src/pages/clients/BulkAttachInboundsModal.tsx

@@ -50,7 +50,6 @@ export default function BulkAttachInboundsModal({
       const skipped = result.skipped?.length ?? 0;
       const errors = result.errors?.length ?? 0;
       if (errors > 0) {
-        console.error('[BulkAttach] failures:', result.errors);
         messageApi.warning(
           t('pages.inbounds.attachClientsResultMixed', { attached, skipped, errors }),
         );

frontend/src/pages/clients/BulkDetachInboundsModal.tsx

@@ -50,7 +50,6 @@ export default function BulkDetachInboundsModal({
       const skipped = result.skipped?.length ?? 0;
       const errors = result.errors?.length ?? 0;
       if (errors > 0) {
-        console.error('[BulkDetach] failures:', result.errors);
         messageApi.warning(
           t('pages.clients.detachFromInboundsResultMixed', { detached, skipped, errors }),
         );