Grow Lehmer modular-inverse fuzz corpora (3-day soak)

[biryukovmaxim]

Grown corpora from a 3-day (72 h) fuzzing soak for the Lehmer modular-inverse implementation in kaspanet/rusty-kaspa#1051.

Targets

All targets ran with strict-asserts enabled (promoted debug_assert! to assert!).

Target	Executions	Corpus entries	Size	Result
u3072	139.8M	21,768	87 MB	0 crashes
u128	1.65B	5,437	22 MB	0 crashes
u192	831M	5,515	22 MB	0 crashes
u256	657M	7,215	29 MB	0 crashes

What each target fuzzes

• u3072: the production lehmer::invert for 3072-bit MuHash elements, cross-checked against num-bigint extended GCD
• u128: construct_uint!(Uint128, 2) arithmetic + LehmerInvert for u128 and Uint128, cross-checked against native u128 and num-bigint
• u192: construct_uint!(Uint192, 3) arithmetic + LehmerInvert, cross-checked against num-bigint (non-power-of-two width)
• u256: construct_uint!(Uint256, 4) arithmetic + LehmerInvert, cross-checked against num-bigint

Coverage reports

• u3072 coverage
• u128 coverage
• u192 coverage
• u256 coverage

Related

• Implementation PR: math: in-repo Lehmer 3072-bit modular inverse + std ceil_log_2 rusty-kaspa#1051