refactor: 完成全站国际化改造，统一多语言支持

此提交完成了全项目的国际化适配：
1. 新增多语言翻译文件与基础配置
2. 替换所有硬编码文本为i18n调用
3. 优化语言切换与文档语言同步逻辑
4. 重构部分业务逻辑以支持动态翻译
5. 移除过时代码与硬编码配置

src/features/player/entry-gate.tsx

@@ -12,7 +12,7 @@ import {
 } from "lucide-react";
 import Image from "next/image";
 import { useRouter, useSearchParams } from "next/navigation";
-import { useCallback, useEffect, useState } from "react";
+import { useCallback, useEffect, useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 
 import { getPlayerMe, getPlayerPing } from "@/api/player";
@@ -97,7 +97,6 @@ export function EntryGate() {
     usePlayerSessionStore();
 
   const [phase, setPhase] = useState<Phase>("loading");
-  const [progress, setProgress] = useState(0);
   const [failureDetails, setFailureDetails] = useState<FailureRow[]>([]);
   const [steps, setSteps] = useState<EntryStep[]>(initialSteps());
 
@@ -107,15 +106,11 @@ export function EntryGate() {
     setSteps((prev) => prev.map((s) => (s.id === stepId ? { ...s, status } : s)));
   }, []);
 
-  const calculateProgress = useCallback((currentSteps: EntryStep[]) => {
-    const doneCount = currentSteps.filter((s) => s.status === "done").length;
-    const inProgressCount = currentSteps.filter((s) => s.status === "in-progress").length;
-    return Math.round(((doneCount + inProgressCount * 0.5) / currentSteps.length) * 100);
-  }, []);
-
-  useEffect(() => {
-    setProgress(calculateProgress(steps));
-  }, [steps, calculateProgress]);
+  const progress = useMemo(() => {
+    const doneCount = steps.filter((s) => s.status === "done").length;
+    const inProgressCount = steps.filter((s) => s.status === "in-progress").length;
+    return Math.round(((doneCount + inProgressCount * 0.5) / steps.length) * 100);
+  }, [steps]);
 
   const handleRetry = useCallback(() => {
     setPhase("loading");

src/features/player/player-session-bar.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { UserRound } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { cn } from "@/lib/utils";
 import { usePlayerSessionStore } from "@/stores/player-session-store";
@@ -10,11 +11,12 @@ import { usePlayerSessionStore } from "@/stores/player-session-store";
  */
 export function PlayerSessionBar({ className }: { className?: string }) {
   const profile = usePlayerSessionStore((s) => s.profile);
+  const { t } = useTranslation("player");
 
   const label =
     profile?.nickname?.trim() ||
     profile?.username?.trim() ||
-    (profile?.id != null ? `玩家 #${profile.id}` : null);
+    (profile?.id != null ? t("player.fallback", { id: profile.id }) : null);
 
   return (
     <div