feat: add event-driven auto backup triggers after wallet changes

[sneurlax]

Fire a debounced auto-backup when a transaction note is saved or an address book contact is created, edited, or deleted.

closes #306

[codecov]

Codecov Report

❌ Patch coverage is 5.63380% with 67 lines in your changes missing coverage. Please review.
✅ Project coverage is 4.84%. Comparing base (8208fe7) to head (85d2435).
⚠️ Report is 11 commits behind head on staging.

Files with missing lines	Patch %	Lines
.../wallet_view/transaction_views/edit_note_view.dart	0.00%	38 Missing ⚠️
lib/services/auto_swb_service.dart	0.00%	12 Missing ⚠️
.../sub_views/backup_frequency_type_select_sheet.dart	14.28%	6 Missing ⚠️
lib/services/address_book_service.dart	0.00%	3 Missing ⚠️
lib/utilities/prefs.dart	0.00%	3 Missing ⚠️
...ib/providers/global/auto_swb_service_provider.dart	0.00%	2 Missing ⚠️
...view/stack_backup_views/edit_auto_backup_view.dart	0.00%	1 Missing ⚠️
...gs_menu/backup_and_restore/create_auto_backup.dart	0.00%	1 Missing ⚠️
lib/utilities/format.dart	75.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           staging    #1377   +/-   ##
========================================
  Coverage     4.84%    4.84%           
========================================
  Files         1092     1092           
  Lines       109141   109167   +26     
========================================
+ Hits          5283     5285    +2     
- Misses      103858   103882   +24     

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