fix: resolve QA report issues across routing, editor, i18n, and pipeline

- Add /tools/:toolId legacy redirect and catch-all 404 page (P1-12, P1-13)
- Add Shift+O dodge/burn/sponge cycle and Ctrl+Y redo shortcut (P1-3, P1-4)
- Fix Fit on Screen menu action to properly compute fit zoom (P1-8)
- Add filename input to editor export dialog (P1-2)
- Fix password validation mismatch: frontend now requires 8 chars (P1-11)
- Add license info to Settings About section (P1-9)
- Replace hardcoded strings in dropzone, files, pipeline with i18n keys (P1-17 to P1-25)
- Add 20+ missing i18n keys to all 21 locale files
- Translate Japanese editor.shapes and settings.aiFeatures sections (P1-19, P1-20)
- Fix RTL: use logical CSS properties in sidebar, files, app-layout (P2-24 to P2-26)
- Add single-file download button to pipeline results (P1-28)
- Fix compress step settings restoration on pipeline load (P1-27)
- Increase mobile nav touch targets to 44px minimum (P2-29)

packages/shared/src/i18n/zh-CN.ts

@@ -36,6 +36,9 @@ export const zhCN: TranslationKeys = {
     unexpectedError: "发生了意外错误。",
     retry: "重试",
     privacyPolicy: "隐私政策",
+    pageNotFound: "Page not found",
+    pageNotFoundDescription: "The page you are looking for does not exist or has been moved.",
+    noToolsFound: "No tools found",
   },
   categories: {
     essentials: "基础工具",
@@ -1619,6 +1622,8 @@ export const zhCN: TranslationKeys = {
       githubLink: "GitHub 仓库",
       docsLink: "文档",
       apiRefLink: "API 参考（Swagger）",
+      licenseLabel: "License:",
+      licenseDescription: "Dual-licensed under AGPLv3 and a commercial license.",
     },
   },
   auth: {
@@ -1758,6 +1763,8 @@ export const zhCN: TranslationKeys = {
     pipelineName: "Pipeline 名称",
     pipelineDescription: "描述（可选）",
     noStepsPrompt: "添加步骤来构建自动化流程",
+    noStepsHeading: "No steps yet",
+    searchToolsPlaceholder: "Search tools...",
     step: "步骤",
   },
   nav: {
@@ -1775,6 +1782,25 @@ export const zhCN: TranslationKeys = {
     uploadTab: "上传",
     fileDetailsAriaLabel: "文件详情",
     fileDetailsHeading: "文件详情",
+    myFiles: "My Files",
+    searchPlaceholder: "Search files...",
+    selectedCount: "{count} selected",
+    fileCount: "{count} files",
+    fileCountSingular: "{count} file",
+    noFilesFound: "No files found",
+    selectFilePrompt: "Select a file to view details",
+    openFile: "Open File",
+    openInPipeline: "Open in Pipeline",
+    name: "Name",
+    format: "Format",
+    size: "Size",
+    dimensions: "Dimensions",
+    version: "Version",
+    toolsUsed: "Tools Used",
+    none: "None",
+    delete: "Delete",
+    pipeline: "Pipeline",
+    download: "Download",
   },
   dropzone: {
     unsupportedFileType: "此工具不支持该文件类型",