feat(l10n): replace legacy %@ format keys with semantic template keys

The Apple catalog carried four stringly-named passthrough keys ("%@",
"%@ · %@", "%@ %@ · %@", "%@%%") left over from the KMP port. They were
never referenced as keys — the composite strings were built inline with
hardcoded separators, so the middot/percent formatting wasn't localizable.

Renames them to proper semantic keys in strings.json:
  - format_separated_pair(first:second:)     "{first} · {second}"
  - format_separated_triple(first:second:third:)
  - battery_level_value(level:)              "{level}%"
and drops the pure-identity "%@". Wires the inline compositions (size ·
status, count files · size, receivers pending · completed, battery level)
to the generated typed accessors. Catalog now validates with zero warnings.

apple/VniDrop/Features/Receive/ReceiveInvitationActions.swift

@@ -111,7 +111,10 @@ struct InvitationReviewPanel: View {
 				let metadata = inspection.metadata
 				VStack(alignment: .leading, spacing: 8) {
 					Text(metadata.transferName).font(VniType.bodyLarge).lineLimit(2)
-					Text("\(metadata.fileCount) \(String(localized: L10n.Metadata.files).lowercased()) · \(formatBytes(metadata.totalSize))")
+					Text(L10n.Format.separatedTriple(
+						first: "\(metadata.fileCount)",
+						second: String(localized: L10n.Metadata.files).lowercased(),
+						third: formatBytes(metadata.totalSize)))
 						.foregroundStyle(colors.foregroundLighter)
 				}
 				.padding(16)