feat(inbounds): add Real client IP presets to capture visitor IP behind CDN/relay

Surface the existing sockopt knobs (acceptProxyProtocol, trustedXForwardedFor) as a guided 'Real client IP' preset selector in the inbound form, so the real visitor IP is recovered behind Cloudflare CDN or an L4 tunnel/relay instead of recording the intermediary address. Presets are mutually exclusive, warn on incompatible transports, and add tooltips, docs, and translations for all locales.

internal/web/translation/zh-TW.json

@@ -557,6 +557,15 @@
         "tcpCongestion": "TCP Congestion",
         "dialerProxy": "Dialer Proxy",
         "trustedXForwardedFor": "信任的 X-Forwarded-For",
+        "trustedXForwardedForHint": "信任此請求標頭以取得真實用戶端 IP（例如 Cloudflare CDN 後的 CF-Connecting-IP）。僅在 WebSocket、HTTPUpgrade 和 XHTTP 傳輸上生效。留空則忽略轉發標頭。",
+        "proxyProtocolHint": "接受 PROXY protocol 標頭，從上游 L4 隧道或中繼（HAProxy、gost、nginx-stream、Xray dokodemo-door）或 Cloudflare Spectrum 取得真實用戶端 IP。上游必須傳送 PROXY protocol。適用於 TCP、WebSocket、HTTPUpgrade 和 gRPC；不適用於 mKCP。",
+        "realClientIp": "真實用戶端 IP",
+        "realClientIpHint": "當流量透過 CDN 或中繼到達此入站時，取得訪客的真實 IP，而非記錄中間節點的位址。選擇一個預設以自動填入下方對應的 sockopt 欄位。這些欄位絕不會在訂閱中傳送給用戶端。",
+        "realClientIpPresetOff": "關閉 / 直連",
+        "realClientIpPresetCloudflare": "Cloudflare CDN",
+        "realClientIpPresetProxyProtocol": "L4 中繼 / Spectrum (PROXY)",
+        "realClientIpTrustedHeaderTransportWarn": "Trusted X-Forwarded-For 僅在 WebSocket、HTTPUpgrade 和 XHTTP 上生效。在目前的傳輸上此標頭將被忽略。",
+        "realClientIpProxyProtocolTransportWarn": "PROXY protocol 不支援此傳輸（mKCP）。請使用 TCP/RAW、WebSocket、HTTPUpgrade、gRPC 或 XHTTP。",
         "addressPortStrategy": "地址+連接埠策略",
         "tryDelayMs": "嘗試延遲 (ms)",
         "prioritizeIPv6": "IPv6 優先",