feat(w2): ship v1.3.0 project pack UI, preload, and E2E

Wire .novel/.novel-all export-import through modals, settings backup, and home bulk export with progress IPC.

Co-authored-by: Cursor <cursoragent@cursor.com>

public/locales/en/translation.json

@@ -442,6 +442,43 @@
   "export.preview": "Preview",
   "export.loading": "Loading…",
   "export.noPreview": "(no preview)",
+  "export.kind": "Export type",
+  "export.kindSubmission": "Submission format (current chapter)",
+  "export.kindNovel": "Bilin project pack (.novel)",
+  "export.novelDesc": "Export the full book database, metadata, and attachments. Restore via Import Book.",
+  "export.exportNovel": "Export project pack",
+  "import.novelHint": "Imports the entire book from a .novel pack (chapters, settings, knowledge).",
+  "import.novelAllHint": "Imports all books from a .novel-all pack. Choose a conflict strategy.",
+  "pack.exportAllTitle": "Export all books",
+  "pack.exportAllDesc": "Package all books and global settings into a .novel-all file.",
+  "pack.estimating": "Estimating size…",
+  "pack.estimatedSize": "Estimated size: {{size}}",
+  "pack.noDest": "No destination selected",
+  "pack.pickDest": "Choose location",
+  "pack.largeExportConfirm": "Export is large ({{size}}). Continue?",
+  "pack.exportAllStart": "Start export",
+  "pack.exportAllSuccess": "All books exported",
+  "pack.exportAllFailed": "Export failed",
+  "pack.exportBookSuccess": "\"{{name}}\" exported as project pack",
+  "pack.exportBookFailed": "Project pack export failed",
+  "pack.exporting": "Exporting…",
+  "pack.cancel": "Cancel",
+  "pack.progress": "Progress {{current}}/{{total}}",
+  "pack.importStrategy": "Import strategy",
+  "pack.strategyNew": "Import all as new books",
+  "pack.strategySkip": "Skip existing books",
+  "pack.strategyOverwrite": "Overwrite matching books",
+  "pack.importAllSuccess": "Import done: {{imported}} new, {{skipped}} skipped, {{overwritten}} overwritten",
+  "backup.desc": "Export books as Bilin project packs for backup, migration, or restore.",
+  "backup.exportCurrentBook": "Export current book",
+  "backup.exportBookBtn": "Export as .novel",
+  "backup.exportAllBooks": "Export all books",
+  "backup.exportAllBtn": "Open bulk export",
+  "backup.noBook": "Open a book in the editor first",
+  "backup.openBookHint": "Open a book in the editor to export a single project pack",
+  "backup.exportBookSuccess": "\"{{name}}\" exported",
+  "backup.exportBookFailed": "Export failed",
+  "backup.formatHint": "Bulk exports over 500 MB require extra confirmation.",
   "submission.title": "Submission Presets",
   "submission.titleFormat": "Title format",
   "submission.indent": "Indent paragraphs",