fix: use UUIDv7 for quote and subscription IDs

[callebtc]

Implements cashubtc/nuts#383

Summary

• use a shared generate_uuid_v7() helper for UUIDv7 generation
• switch mint quote IDs and melt quote IDs to UUIDv7
• switch websocket subscription IDs to UUIDv7
• remove the old quote-specific/random hash helper usage

Testing

• poetry run pytest -q tests/test_quote_ids.py tests/wallet/test_wallet_subscription_unit.py tests/wallet/test_wallet.py::test_request_mint tests/wallet/test_wallet.py::test_mint tests/wallet/test_wallet.py::test_melt tests/wallet/test_wallet.py::test_get_melt_quote_state tests/test_mint_rpc_cli.py::test_get_mint_quote tests/test_mint_rpc_cli.py::test_get_melt_quote tests/test_mint_rpc_cli.py::test_get_quote_ttl_mint_quote tests/test_mint_rpc_cli.py::test_get_quote_ttl_melt_quote

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.05%. Comparing base (31e3ae3) to head (e2bfea1).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1023      +/-   ##
==========================================
+ Coverage   75.03%   75.05%   +0.02%     
==========================================
  Files         111      111              
  Lines       12239    12245       +6     
==========================================
+ Hits         9183     9190       +7     
+ Misses       3056     3055       -1     

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