Add compact state filters

[crodas]

Description

Following ecash today means naming it: checkstate carries the exact Y values, quote polling carries the quote id, and a seed restore hands the mint every recovered Y including the unspent ones. Compact state filters replace that with public Golomb-Rice filters, published once per epoch and identical for every requester, that a wallet tests locally. A wallet learns that its ecash was spent, or its quote paid, without telling the mint which, and makes an identifying request only when something has probably happened.

The mint records one element per observable state change in the same transaction that makes it, builds one filter per closed epoch, and serves them as pages that never change again. The wallet sweeps new filters, tests its own objects offline, and confirms a match through NUT-07 or the quote endpoint before acting on it, since a filter is never authoritative. Restore and the pending-proof and quote sweeps prefer filters whenever the mint advertises them and fall back otherwise.

Spec: cashubtc/nuts#433

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Notes to the reviewers

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Suggested CHANGELOG Updates

CHANGED

ADDED

REMOVED

FIXED

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Checklist

• I followed the code style guidelines
• I ran just quick-check before committing
• If the Wallet API was modified (added/removed/changed), I have reflected those changes in the FFI bindings (crates/cdk-ffi)

[codecov]

Codecov Report

❌ Patch coverage is 78.29060% with 254 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.92%. Comparing base (bb139ef) to head (b752c07).

Files with missing lines	Patch %	Lines
crates/cdk/src/wallet/state_filters/mod.rs	53.67%	82 Missing ⚠️
crates/cdk-mintd/src/lib.rs	26.66%	22 Missing ⚠️
crates/cdk-axum/src/filters_handlers.rs	0.00%	21 Missing ⚠️
crates/cdk-mintd/src/env_vars/state_filters.rs	43.24%	21 Missing ⚠️
crates/cdk/src/wallet/state_filters/cursor.rs	64.28%	20 Missing ⚠️
crates/cdk/src/mint/state_filters/mod.rs	80.64%	18 Missing ⚠️
crates/cdk-common/src/error.rs	0.00%	14 Missing ⚠️
crates/cdk/src/mint/state_filters/service.rs	91.66%	11 Missing ⚠️
crates/cdk-axum/src/lib.rs	0.00%	8 Missing ⚠️
crates/cdk/src/mint/mod.rs	84.00%	8 Missing ⚠️
... and 10 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2477      +/-   ##
==========================================
- Coverage   78.93%   78.92%   -0.02%     
==========================================
  Files         387      398      +11     
  Lines      105293   106391    +1098     
==========================================
+ Hits        83115    83968     +853     
- Misses      22178    22423     +245     

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