feat: implement seed phrase backup reminder modal

Add comprehensive seed phrase backup reminder system to encourage users
to secure their identity after creating content.

Core Features:
- Modal dialog with "Backup Identifier Seed" and "Remind me Later" options
- 24-hour localStorage cooldown to prevent notification fatigue
- 1-second delay after success messages for better UX flow
- Focuses on claim creation actions, not confirmations

New Files:
- src/utils/seedPhraseReminder.ts: Core utility for reminder logic
- doc/seed-phrase-reminder-implementation.md: Comprehensive documentation

Trigger Points Added:
- Profile saving (AccountViewView)
- Claim creation (ClaimAddRawView, GiftedDialog, GiftedDetailsView)
- Offer creation (OfferDialog)
- QR code view exit (ContactQRScanFullView, ContactQRScanShowView)

Technical Implementation:
- Uses existing notification group modal system from App.vue
- Integrates with PlatformServiceMixin for account settings access
- Graceful error handling with logging fallbacks
- Non-blocking implementation that doesn't affect main functionality
- Modal stays open indefinitely (timeout: -1) until user interaction

User Experience:
- Non-intrusive reminders that respect user preferences
- Clear call-to-action for security-conscious users
- Seamless integration with existing workflows
- Maintains focus on content creation rather than confirmation actions

src/views/ContactQRScanFullView.vue

@@ -144,6 +144,7 @@ import {
   QR_TIMEOUT_LONG,
 } from "@/constants/notifications";
 import { createNotifyHelpers, NotifyFunction } from "../utils/notify";
+import { showSeedPhraseReminder } from "@/utils/seedPhraseReminder";
 
 interface QRScanResult {
   rawValue?: string;
@@ -622,6 +623,15 @@ export default class ContactQRScanFull extends Vue {
    */
   async handleBack() {
     await this.cleanupScanner();
+
+    // Show seed phrase backup reminder if needed
+    try {
+      const settings = await this.$accountSettings();
+      showSeedPhraseReminder(!!settings.hasBackedUpSeed, this.$notify);
+    } catch (error) {
+      logger.error("Error checking seed backup status:", error);
+    }
+
     this.$router.back();
   }