Remove paid field in MeltQuote

[KvngMikey]

Follow up to #838

Fully Fixes #855

Supercedes #870

Summary

This PR completes the deprecation and removal of the legacy paid fields in melt_quotes, fully migrating the system to rely on the state field as the single source of truth for quote payment status.

• Tests depending on the legacy paid field were updated.
• Foreign-key–related failures caused by table recreation were fixed by explicitly restoring the correct schema during the migration.

[Copilot]

Pull request overview

Note

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Removes the deprecated paid boolean from melt quote storage/models/APIs and shifts behavior/tests to rely solely on state.

Changes:

• Dropped paid from PostMeltQuoteResponse and related API response construction paths.
• Updated DB write paths and added a migration to remove the paid column from melt_quotes.
• Adjusted tests to assert on state instead of deprecated boolean accessors/fields.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/mint/test_mint_api.py	Removes obsolete commented assertions around deprecated paid behavior.
tests/fuzz/test_fuzz_core.py	Updates fuzz assertions to use state comparisons instead of paid/unpaid/pending accessors.
cashu/wallet/v1_api.py	Stops including paid in melt quote request/response field selection.
cashu/mint/router.py	Removes paid from API response creation for melt quote retrieval.
cashu/mint/migrations.py	Adds migration to remove paid column from melt_quotes (SQLite table rebuild / Postgres DROP COLUMN).
cashu/mint/ledger.py	Replaces boolean paid checks with state comparisons.
cashu/mint/crud.py	Removes paid column from insert parameters for melt_quotes.
cashu/mint/auth/crud.py	Removes paid column usage in insert/update; stores state via .value.
cashu/core/models/melt_quote.py	Removes deprecated paid field from PostMeltQuoteResponse.
cashu/core/base.py	Removes backwards-compat mapping from legacy paid responses to state.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.07%. Comparing base (31e3ae3) to head (1ab1bf4).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1024      +/-   ##
==========================================
+ Coverage   75.03%   75.07%   +0.04%     
==========================================
  Files         111      111              
  Lines       12239    12243       +4     
==========================================
+ Hits         9183     9192       +9     
+ Misses       3056     3051       -5     

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