Add recurse fuzz subexpression map

[prozacchiwawa]

Summary

• Add JSON resources mapping modern Chialisp subexpressions to classic equivalents for both recurse and assign fuzz regression programs.
• Wire the resource fuzz test through those maps so each generated modern variation has an analogous classic variation produced from the same placeholder/template expansion.
• Add map/source validation to ensure mapped forms parse and exist in their expected resource programs.
• Constrain assign dummy and tail-call fuzz targets so nested strlen arguments and nth indices remain valid while paired variations are generated.

Testing

• python3 -m json.tool resources/tests/fuzz_test_assign_bug_1_modern_classic_subexpression_map.json >/tmp/assign-map.json && python3 -m json.tool resources/tests/fuzz_test_recurse_bug_0_modern_classic_subexpression_map.json >/tmp/recurse-map.json
• cargo test fuzz_resource_subexpression_maps_match_sources
• cargo test fuzz_resource_program_variations_run -- --nocapture
• cargo test fuzz_resource