feat: 全面优化 SEO 元数据、结构化数据和站点地图

为所有工具页面添加 canonical URL、keywords、SoftwareApplication 和
BreadcrumbList 结构化数据，优化标题和描述以包含搜索意图关键词，
更新站点地图日期和优先级，移除无效的 SearchAction，新增 PWA manifest。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app/(dashboard)/tools/image-compress/layout.tsx

@@ -1,5 +1,6 @@
 import type { Metadata } from "next";
 import { headers } from "next/headers";
+import { SoftwareApplicationStructuredData, BreadcrumbStructuredData } from "@/components/seo/StructuredData";
 
 export async function generateMetadata(): Promise<Metadata> {
   const headersList = await headers();
@@ -7,25 +8,61 @@ export async function generateMetadata(): Promise<Metadata> {
   const lang = acceptLanguage.includes("zh") ? "zh" : "en";
 
   const titles = {
-    en: "Image Compression - Optimize Images for Web & Mobile",
-    zh: "图片压缩 - 为网页和移动端优化图片",
+    en: "Image Compression - Optimize PNG, JPEG, WebP Online Free",
+    zh: "图片压缩 - 免费在线优化 PNG、JPEG、WebP 图片",
   };
 
   const descriptions = {
-    en: "Optimize images for web and mobile without quality loss. Support for batch processing and format conversion including PNG, JPEG, WebP.",
-    zh: "为网页和移动端优化图片，不影响质量。支持批量处理和格式转换，包括 PNG、JPEG、WebP。",
+    en: "Free online image compressor. Optimize PNG, JPEG, WebP, AVIF images without quality loss. Batch processing, format conversion, browser-based with no uploads required.",
+    zh: "免费在线图片压缩工具。无损优化 PNG、JPEG、WebP、AVIF 图片。支持批量处理、格式转换，浏览器本地处理无需上传。",
   };
 
+  const keywords = {
+    en: [
+      "image compression",
+      "image compressor online",
+      "compress PNG",
+      "compress JPEG",
+      "WebP converter",
+      "image optimizer",
+      "batch image compression",
+      "reduce image size",
+      "AVIF converter",
+      "browser-based",
+    ],
+    zh: [
+      "图片压缩",
+      "在线图片压缩",
+      "PNG压缩",
+      "JPEG压缩",
+      "WebP转换",
+      "图片优化",
+      "批量压缩",
+      "缩小图片",
+      "AVIF转换",
+      "浏览器端",
+    ],
+  };
+
+  const baseUrl = process.env.NEXT_PUBLIC_SITE_URL || "https://kymr.top";
+
   return {
     title: titles[lang],
     description: descriptions[lang],
+    keywords: keywords[lang],
+    alternates: {
+      canonical: `${baseUrl}/tools/image-compress`,
+    },
     openGraph: {
       title: titles[lang],
       description: descriptions[lang],
+      url: `${baseUrl}/tools/image-compress`,
+      type: "website",
     },
     twitter: {
       title: titles[lang],
       description: descriptions[lang],
+      card: "summary_large_image",
     },
   };
 }
@@ -35,5 +72,23 @@ export default function ImageCompressLayout({
 }: {
   children: React.ReactNode;
 }) {
-  return children;
+  return (
+    <>
+      <SoftwareApplicationStructuredData
+        name="Image Compressor - KYMR.TOP"
+        description="Free online image compression tool. Optimize PNG, JPEG, WebP, AVIF images without quality loss. Browser-based processing with no uploads."
+        url="/tools/image-compress"
+        category="MultimediaApplication"
+        operatingSystem="Any (Browser-based)"
+      />
+      <BreadcrumbStructuredData
+        items={[
+          { name: "Home", url: "/" },
+          { name: "Tools", url: "/tools" },
+          { name: "Image Compression", url: "/tools/image-compress" },
+        ]}
+      />
+      {children}
+    </>
+  );
 }