feat(export): separate resume/cover-letter downloads, redesign dialog, add Markdown export (#3217)

* feat(export): separate resume/cover-letter downloads, redesign dialog, add Markdown

Let people export the resume and cover letter as distinct documents, and add a
Markdown format alongside PDF / DOCX / JSON (handy for AI agents).

- Server/API: scope PDF generation and download URLs to a resume/cover-letter target.
- Export domain: getResumeExportData + resumeHasCoverLetter in @reactive-resume/resume.
- Redesign the download dialog: one global "What to export" scope toggle (Tabs) plus
  flattened per-format rows, reusing existing UI components and design language.
- Add Markdown export (@reactive-resume/resume/markdown) with a small tiptap-HTML converter.
- Fix blank section headings in DOCX and Markdown by injecting the locale-aware
  section-title resolver (titles are stored empty and resolved at render time).
- Locale catalogs updated for the new strings.

* test(e2e): open the download dialog before exporting JSON

The JSON export moved into the redesigned download dialog, so the spec now opens
the dialog from the Export sidebar section before clicking "Download JSON".

apps/web/src/features/resume/public/public-resume.tsx

@@ -33,7 +33,7 @@ export function PublicResumeRoute() {
 						{basics.name && <h1 className="font-semibold text-2xl tracking-tight">{basics.name}</h1>}
 						{basics.headline && <p className="text-muted-foreground">{basics.headline}</p>}
 					</div>
-					<Button onClick={onDownloadPDF} disabled={isExporting}>
+					<Button onClick={() => void onDownloadPDF()} disabled={isExporting}>
 						{isExporting ? (
 							<CircleNotchIcon className="size-4 animate-spin" />
 						) : (
@@ -62,7 +62,7 @@ export function PublicResumeRoute() {
 				size="icon-lg"
 				variant="outline"
 				disabled={isExporting}
-				onClick={onDownloadPDF}
+				onClick={() => void onDownloadPDF()}
 				aria-label={t`Download PDF`}
 				title={t`Download PDF`}
 				className="fixed right-6 bottom-6 z-50 rounded-full bg-background/95 opacity-70 shadow-lg backdrop-blur transition-opacity hover:opacity-100 print:hidden"