feat: compute spreads during benchmarks

[lbkolev]

• invoking benchmarks now computes and stores the spreads; the datasets are also regenerated
• a new optionality has been added that permits one to append a jitodontfront acc as the last in the list of remaining_accounts;

without jitodontfront:

$ ./target/release/pmm-sim single --amount-in=100 --pmms=tessera --weights=100 --src-token=WSOL --dst-token=USDC --jit-accounts=false --spoof=jupiter --jitodontfront=false
..
2026-03-04T11:42:04.297875Z  INFO ThreadId(01) pmm_sim: 900: src_token=wsol dst_token=usdc routes=[[Route { dexes: [Tessera], weights: [100] }]] amount_in=100.0 amount_out=8247.434645 cu=94721

with jitodontfront:

$ ./target/release/pmm-sim single --amount-in=100 --pmms=tessera --weights=100 --src-token=WSOL --dst-token=USDC --jit-accounts=false --spoof=jupiter --jitodontfront=true --jitodontfront-acc=jitodontfront11111111111JustUseJupiterU1tra
..
2026-03-04T11:41:55.639219Z  INFO ThreadId(01) pmm_sim: 900: src_token=wsol dst_token=usdc routes=[[Route { dexes: [Tessera], weights: [100] }]] amount_in=100.0 amount_out=8249.084462 cu=94981