feat(amneziawg): remove the vestigial routeThroughXray toggle from the UI

Hard cutover, part 4: the embedded path has no opt-in gate for Xray
routing at all (every peer's traffic already goes through Xray's own
SOCKS5 relay unconditionally -- see xray.go's injectAmneziawgnetSocks), so
a toggle that no longer does anything would just confuse admins. Removed
from the form (amneziawg.tsx), the per-protocol Zod schema and its
new-inbound default, and the routeThroughXray/routeThroughXrayHint i18n
strings across all 13 locales.

The Go-side field stays (see internal/amneziawg's ServerSettings/Instance,
already annotated as vestigial in the previous commit) for backward
compatibility with existing stored settings -- z.object's default
unknown-key stripping means the form simply drops it from an existing
inbound's settings on its next save, no migration needed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

internal/web/translation/id-ID.json

@@ -1654,8 +1654,6 @@
         "ipv6SubnetHint": "mis. fd86:ea04:1115::/64. Wajib diisi saat IPv6 diaktifkan.",
         "ipv6ExternalInterface": "NIC Eksternal IPv6",
         "ipv6ExternalInterfaceHint": "NIC host untuk entri proxy NDP. Biarkan kosong untuk menggunakan NIC Eksternal.",
-        "routeThroughXray": "Rutekan melalui Xray",
-        "routeThroughXrayHint": "Nonaktif secara default: tunnel tidak bergantung pada Xray sama sekali. Jika diaktifkan, trafik setiap klien dialihkan ke bridge Xray milik inbound ini sendiri, dan outbound sebenarnya dipilih dari halaman Routing seperti protokol lainnya.",
         "obfuscation": "Parameter obfuskasi",
         "regenerateObfuscation": "Buat ulang",
         "jc": "Jc (jumlah paket sampah)",