fix(i18n): escape literal braces in configTransfer pastePlaceholder

The message '{"kind": "evoscientist.model-registry", ...}' is malformed
ICU: intl-messageformat throws MALFORMED_ARGUMENT at render time and
next-intl's type inference extracts a garbage argument name, so t()
neither typechecks nor renders. Wrap the braces in apostrophe quotes.

src/i18n/messages/en/configTransfer.ts

@@ -14,7 +14,7 @@ const configTransfer = {
         "Import a previously exported JSON file. It may contain plaintext API keys.",
       fileLabel: "Choose a .json export file",
       pasteLabel: "Or paste the export JSON",
-      pastePlaceholder: '{"kind": "evoscientist.model-registry", ...}',
+      pastePlaceholder: "'{'\"kind\": \"evoscientist.model-registry\", ...'}'",
       errors: {
         too_large: "The file is larger than 1 MB.",
         invalid_json: "The content is not valid JSON.",

src/i18n/messages/zh/configTransfer.ts

@@ -12,7 +12,7 @@ const configTransfer = {
       description: "导入先前导出的 JSON 文件，文件可能包含明文 API 密钥。",
       fileLabel: "选择 .json 导出文件",
       pasteLabel: "或粘贴导出的 JSON",
-      pastePlaceholder: '{"kind": "evoscientist.model-registry", ...}',
+      pastePlaceholder: "'{'\"kind\": \"evoscientist.model-registry\", ...'}'",
       errors: {
         too_large: "文件超过 1 MB。",
         invalid_json: "内容不是有效的 JSON。",