feat(studio): make migration home a single-column workspace

frontend/README.md

@@ -344,6 +344,13 @@ See [deployment and operation](service/studio_release_notifier/README.md).
   versions; any version can be restored into the intelligent-development flow
   for another intent-driven iteration after the temporary migration environment
   has ended.
+  The workspace is a single-column page without a side navigation: the home is
+  the upload entry followed by recent migrations (five by default, expandable
+  in place, with expired environments offered as view-only), “已迁移项目” is a
+  top-bar entry that opens the saved-project library, and returning home or
+  opening the project library never stops a running migration. Capability and
+  session-list failures are reported separately so the upload entry stays
+  usable and each failure offers its own retry.
   Pencil icons beside project and version names open the existing-style name
   dialog; the check icon saves and the close icon cancels. Names are normalized
   and trimmed, allow 1–128 Unicode characters, and reject control/invisible

frontend/src/i18n/resources/en-US/migrations.json

@@ -145,9 +145,11 @@
     "reselect": "Select again",
     "selectZip": "Select ZIP",
     "continue": "Continue upload",
-    "start": "Start migration",
+    "start": "Upload and analyze",
     "inputAria": "Select a local project ZIP",
-    "retention": "The temporary migration environment is retained for 1 hour after creation. Successfully saved source versions are unaffected."
+    "retention": "The temporary migration environment is retained for 1 hour after creation. Successfully saved source versions are unaffected.",
+    "uploading": "Uploading…",
+    "sizeHint": "Project ZIP, up to {{size}}"
   },
   "deployment": {
     "requiredPlaceholder": "Enter {{key}}",
@@ -160,11 +162,21 @@
     "title": "Migrate existing project",
     "newMigration": "New migration",
     "recent": "Recent migrations",
-    "sessionsAria": "Migration sessions",
     "loadingSessions": "Loading migration sessions…",
     "noSessions": "No migration sessions",
     "heading": "Migrate an existing Agent project",
-    "intro": "Upload a local project ZIP. Codex will first perform a read-only analysis, then ask you to confirm the migration method."
+    "intro": "Upload a local project ZIP. Codex will first perform a read-only analysis, then ask you to confirm the migration method.",
+    "backToHome": "Migration home",
+    "navigation": "Migration navigation",
+    "showMore": "Show more",
+    "showLess": "Show less",
+    "projectName": "Project name",
+    "status": "Status",
+    "createdAt": "Created",
+    "actions": "Actions",
+    "openTask": "Open migration {{name}}",
+    "continueTask": "Continue",
+    "viewTask": "View"
   },
   "actions": {
     "stop": "Stop migration",
@@ -178,8 +190,6 @@
     "defaultReason": "Dev Sandbox is currently unavailable. Contact your administrator to check the configuration."
   },
   "conversation": {
-    "requestZip": "Provide a local project ZIP. After upload, I’ll identify the framework, entry point, and migration boundaries, then ask you to confirm the migration method before making changes.",
-    "zipHint": "Only local ZIP files are supported, up to {{size}}. The migration environment is retained for 1 hour after creation.",
     "creatingSandbox": "Creating Dev Sandbox",
     "initializing": "Initializing the migration workspace and checking AgentKit CLI, Codex, and migration capabilities. The project will upload automatically when the environment is ready.",
     "elapsed": "Elapsed: {{duration}}",

frontend/src/i18n/resources/zh-CN/migrations.json

@@ -145,9 +145,11 @@
     "reselect": "重新选择",
     "selectZip": "选择 ZIP",
     "continue": "继续上传",
-    "start": "开始迁移",
+    "start": "上传并分析",
     "inputAria": "选择本地项目 ZIP",
-    "retention": "临时迁移环境从创建完成起保留 1 小时；保存成功的源码版本不受影响。"
+    "retention": "临时迁移环境从创建完成起保留 1 小时；保存成功的源码版本不受影响。",
+    "uploading": "上传中…",
+    "sizeHint": "支持项目 ZIP，最大 {{size}}"
   },
   "deployment": {
     "requiredPlaceholder": "请输入 {{key}}",
@@ -160,11 +162,21 @@
     "title": "从存量迁移",
     "newMigration": "新建迁移",
     "recent": "最近迁移",
-    "sessionsAria": "迁移会话",
     "loadingSessions": "正在读取迁移会话…",
     "noSessions": "暂无迁移会话",
     "heading": "迁移存量 Agent 项目",
-    "intro": "上传本地项目 ZIP，Codex 将先进行只读分析，再由你确认迁移方式。"
+    "intro": "上传本地项目 ZIP，Codex 将先进行只读分析，再由你确认迁移方式。",
+    "backToHome": "迁移首页",
+    "navigation": "迁移导航",
+    "showMore": "查看更多",
+    "showLess": "收起",
+    "projectName": "项目名称",
+    "status": "状态",
+    "createdAt": "创建时间",
+    "actions": "操作",
+    "openTask": "查看迁移 {{name}}",
+    "continueTask": "继续",
+    "viewTask": "查看"
   },
   "actions": {
     "stop": "终止迁移",
@@ -178,8 +190,6 @@
     "defaultReason": "Dev Sandbox 暂不可用，请联系管理员检查配置。"
   },
   "conversation": {
-    "requestZip": "请提供本地项目 ZIP。上传后我会识别框架、入口和迁移边界，并在执行实际迁移前请你确认迁移方式。",
-    "zipHint": "仅支持本地 ZIP，最大 {{size}}；迁移环境从创建起保留 1 小时。",
     "creatingSandbox": "正在创建 Dev Sandbox",
     "initializing": "正在初始化迁移工作目录，并检查 AgentKit CLI、Codex 和迁移能力。环境就绪后将自动上传项目。",
     "elapsed": "已等待 {{duration}}",

frontend/src/migrations/MigratedProjectsPage.tsx

@@ -43,12 +43,6 @@ export function MigratedProjectsPage({
   return (
     <>
       <main className="migration-main migration-projects-page">
-        <header className="migration-main__header">
-          <div>
-            <h2>{t("projects.title")}</h2>
-            <p>{t("projects.description")}</p>
-          </div>
-        </header>
         <div className="migration-projects-page__content">
           <IntelligentProjectLibrary
             origin="migration"