fix: fuzzer issue gen

[joseph-isaacs]

Fix up the fuzzer issue gen to correctly dedup and issues and truncate the issue body so its under 65k.

Tested and looks good

[codspeed-hq]

Merging this PR will degrade performance by 11.52%

❌ 3 regressed benchmarks
✅ 1132 untouched benchmarks
⏩ 1268 skipped benchmarks¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	take_map[(0.05, 1.0)]	3.1 ms	3.4 ms	-10.09%
❌	Simulation	take_map[(0.05, 0.5)]	1.7 ms	1.9 ms	-10.75%
❌	Simulation	take_map[(0.1, 0.5)]	2.1 ms	2.3 ms	-11.52%

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_{Comparing ji/fix-up-fuzzer (6e18cc0) with develop (4c997c9)}

Footnotes

1. 1268 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩