feat(wallet): add configurable min_output_value filter

[noahjoeris]

Description

Adds a runtime-only min_output_value: Option<Amount> setting to Wallet for dust/spam filtering. It filters wallet-visible spendable value in balance, list_unspent, and automatic coin selection without changing accounting functions.

Closes #375

Notes to the reviewers

• Named min_output_value rather than dust_threshold to avoid confusion with the existing coin selection dust_threshold and Bitcoin's relay dust policy.
• Not persisted; treated as a runtime filter applied on top of stored wallet state. It can be provided when creating/loading via CreateParams::min_output_value() / LoadParams::min_output_value(), or changed at runtime via Wallet::set_min_output_value().
• Filtering is applied in bdk_wallet, not pushed down into bdk_chain.

Changelog notice

• Added runtime min_output_value support to Wallet, CreateParams, and LoadParams
• balance, list_unspent, and coin selection now honor min_output_value

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran just p before pushing

New Features:

• I've added tests for the new feature
• I've added docs for the new feature

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.15%. Comparing base (275406e) to head (b0afce7).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #427      +/-   ##
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+ Coverage   80.96%   81.15%   +0.19%     
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  Files          24       24              
  Lines        5489     5530      +41     
  Branches      247      247              
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+ Hits         4444     4488      +44     
+ Misses        968      965       -3     
  Partials       77       77              

Flag	Coverage Δ
rust	81.15% <100.00%> (+0.19%)	⬆️

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[Dmenec]

Concept ACK. Related with the sent_and_received / net_value approach, why apply min_output_value to transaction accounting methods? A tx already broadcast moved exactly what it moved on-chain. I'd expect the threshold to act as an operational filter for UTXO management, but not change how historical transactions are reported. Maybe I'm ignoring some use case...

Also, #431 rewrites balance() for trusted/untrusted pending classification, worth a look as both touch the same function.

[noahjoeris]

Yes agree, thanks. I think I included it because #375 asked for it too. Bit weird in hindsight and can cause inconsistencies. So the key parts to filter are list_unspent, balance, and coin selection. I updated in latest push.
Will rebase once your PR lands