Add fees

[callebtc]

Implements cashubtc/nuts#126

• Fee reponds with input_fee_ppk in keysets response
• Wallet: New recursive coinselection algorithm
• Wallet detects keyset rotations and active state changes
• Wallet splits entire inactive balance if it detects a rotation

[codecov]

Codecov Report

Attention: Patch coverage is 86.34312% with 121 lines in your changes are missing coverage. Please review.

Project coverage is 65.63%. Comparing base (3b2f1aa) to head (abf3b6c).
Report is 11 commits behind head on main.

❗ Current head abf3b6c differs from pull request most recent head 237b212

Please upload reports for the commit 237b212 to get more accurate results.

Files	Patch %	Lines
cashu/wallet/transactions.py	70.45%	26 Missing ⚠️
cashu/mint/crud.py	0.00%	20 Missing ⚠️
cashu/wallet/wallet.py	88.12%	19 Missing ⚠️
cashu/wallet/v1_api.py	93.83%	14 Missing ⚠️
cashu/wallet/proofs.py	85.55%	13 Missing ⚠️
cashu/mint/verification.py	78.78%	7 Missing ⚠️
cashu/wallet/cli/cli.py	60.00%	4 Missing ⚠️
cashu/core/errors.py	70.00%	3 Missing ⚠️
cashu/mint/router_deprecated.py	0.00%	3 Missing ⚠️
cashu/wallet/cli/cli_helpers.py	40.00%	3 Missing ⚠️
... and 7 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #503      +/-   ##
==========================================
- Coverage   69.62%   65.63%   -3.99%     
==========================================
  Files          76       81       +5     
  Lines        6913     7302     +389     
==========================================
- Hits         4813     4793      -20     
- Misses       2100     2509     +409     

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