feat: single address policy

[r4mmer]

Acceptance Criteria

Create a single address policy so the wallet facade can work in a single address mode.

Security Checklist

• Make sure you do not include new dependencies in the project unless strictly necessary and do not include dev-dependencies as production ones. More dependencies increase the possibility of one of them being hijacked and affecting us.

[codecov]

Codecov Report

❌ Patch coverage is 62.50000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.97%. Comparing base (21ba6c1) to head (4dd2370).

Files with missing lines	Patch %	Lines
src/wallet/wallet.ts	37.50%	5 Missing ⚠️
src/utils/storage.ts	75.00%	0 Missing and 1 partial ⚠️

❌ Your patch check has failed because the patch coverage (62.50%) is below the target coverage (70.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #899      +/-   ##
==========================================
- Coverage   85.00%   84.97%   -0.04%     
==========================================
  Files         113      113              
  Lines        8389     8404      +15     
  Branches     1832     1847      +15     
==========================================
+ Hits         7131     7141      +10     
- Misses       1229     1233       +4     
- Partials       29       30       +1     

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