feat(SPV-1465): add source transaction inputs HEX storage.

[mgosek-4chain]

Pull Request Checklist

• 📖 I created my PR using provided : CODE_STANDARDS
• 📖 I have read the short Code of Conduct: CODE_OF_CONDUCT
• 🏠 I tested my changes locally.
• ✅ I have provided tests for my changes.
• 📝 I have used conventional commits.
• 📗 I have updated any related documentation.
• 💾 PR was issued based on the Github or Jira issue.

[github-actions]

Manual Tests

💚 Manual testing by @chris-4chain resulted in success.

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

Attention: Patch coverage is 6.30631% with 208 lines in your changes missing coverage. Please review.

Project coverage is 36.36%. Comparing base (138abf7) to head (812e3b2).

Files with missing lines	Patch %	Lines
engine/v2/database/repository/transactions.go	0.00%	70 Missing ⚠️
engine/v2/transaction/record/tx_flow.go	0.00%	32 Missing ⚠️
engine/testabilities/fixture_faucet.go	0.00%	26 Missing ⚠️
engine/v2/database/repository/operations.go	0.00%	16 Missing ⚠️
engine/v2/transaction/txmodels/new_transaction.go	0.00%	13 Missing ⚠️
engine/v2/database/tracked_transaction.go	0.00%	8 Missing ⚠️
engine/testabilities/fixture_engine.go	0.00%	7 Missing ⚠️
engine/v2/database/repository/all.go	0.00%	7 Missing ⚠️
...lines/testabilities/fixture_outline_transaction.go	0.00%	5 Missing ⚠️
...nes/testabilities/mock_transaction_beef_service.go	0.00%	5 Missing ⚠️
... and 8 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #905      +/-   ##
==========================================
- Coverage   36.67%   36.36%   -0.31%     
==========================================
  Files         410      412       +2     
  Lines       19209    19365     +156     
==========================================
- Hits         7044     7043       -1     
- Misses      11587    11742     +155     
- Partials      578      580       +2     

Flag	Coverage Δ
unittests	36.36% <6.30%> (-0.31%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
engine/client_internal.go	69.90% <100.00%> (+0.42%)	⬆️
engine/v2/transaction/beef/beef_service.go	67.44% <100.00%> (ø)
...utlines/utxo/internal/sql/inputs_query_composer.go	100.00% <100.00%> (ø)
engine/v2/database/models.go	0.00% <0.00%> (ø)
...ansaction/beef/testabilities/mock_tx_repository.go	0.00% <0.00%> (ø)
engine/v2/transaction/record/service.go	0.00% <0.00%> (ø)
...ions/testabilities/assert_transactions_endpoint.go	0.00% <0.00%> (ø)
...nal/testabilities/ability_transactions_endpoint.go	0.00% <0.00%> (ø)
...ansaction/outlines/transaction_outlines_service.go	81.35% <63.63%> (-6.98%)	⬇️
engine/v2/transaction/record/record_outline.go	0.00% <0.00%> (ø)
... and 11 more

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 138abf7...812e3b2. Read the comment docs.