fix: fetch targeted Amazon orders directly

[eshaffer321]

What changed

• use the provider's direct order lookup when -order-id is supplied
• preserve provider-fetch audit logging for targeted requests
• add a regression test and bug-fix documentation

Why

Amazon -order-id recovery runs were filtering only after a full order-history scan. That made a one-order run fetch every order and its payment details, often taking long enough for Amazon to reject the session before the requested order was processed.

Impact

Targeted Amazon recovery runs now fetch only the requested order. Normal date-range syncs keep the existing bulk-fetch behavior.

Validation

• go test ./...
• pre-commit golangci-lint run --timeout=5m
• pre-commit go vet ./...
• production-verified against two exact Amazon orders on the wife account
• rebased onto latest origin/main before opening this PR

[codecov]

Codecov Report

❌ Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.34%. Comparing base (b7a2788) to head (860cbfc).

Files with missing lines	Patch %	Lines
internal/application/sync/fetch.go	86.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #75      +/-   ##
==========================================
+ Coverage   64.29%   64.34%   +0.05%     
==========================================
  Files          49       49              
  Lines        6560     6575      +15     
==========================================
+ Hits         4218     4231      +13     
- Misses       2036     2037       +1     
- Partials      306      307       +1     

Flag	Coverage Δ
unittests	64.34% <86.66%> (+0.05%)	⬆️

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Files with missing lines	Coverage Δ
internal/application/sync/fetch.go	48.95% <86.66%> (+4.41%)	⬆️

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