refactor(apple): make InvitationError typed and localize NFC prompts

Replace the free-form InvitationError.message(String) case with semantic
cases mapped to L10n keys at the UI boundary (Error.uiText), so user-facing
error text is localized instead of substring-matched from English blobs.
.raw(String) remains only for genuinely dynamic system/core messages.

Localize the CoreNFC alertMessage prompts via existing L10n keys, and add
SwiftLint rules (raw_alert_message, raw_invitation_error) to catch raw
alert strings and literal .raw("…") errors going forward.

apple/VniDrop/Features/Settings/BugReportService.swift

@@ -20,7 +20,7 @@ protocol BugReportService {
 /// Offline-safe no-op used until the diagnostics transport is configured.
 struct NoopBugReportService: BugReportService {
 	func submit(_ draft: BugReportDraft, deviceInfo: DeviceInfo?) async -> Result<Void, Error> {
-		.failure(InvitationError.message("Bug reporting is not configured"))
+		.failure(InvitationError.bugReportingUnavailable)
 	}
 	func previewLogBytes() async -> Int { 0 }
 }