[Aursen]

Summary

Behavior-preserving cleanup across litesvm, persistence, token, loader and cpi-tree (−333 lines). The main change is the transaction pipeline:

 send_transaction / simulate_transaction
-  execute_transaction | execute_transaction_no_verify
-  execute_transaction_readonly | execute_transaction_no_verify_readonly
-    map_sanitize_result(sanitize_transaction[_no_verify][_inner])
-      execute_sanitized_transaction[_readonly]
-        check_and_process_transaction -> CheckAndProcessTransactionSuccess{Core}
-          process_transaction -> 6-tuple
+  sanitize_transaction(tx, self.sigverify)
+    check_and_process_transaction -> (ExecutionResult, payer)   // send_transaction then charges the fee
+      process_transaction -> ProcessedTransaction

Also: AccountsDb::load_program and try_program_elf_bytes share one ELF-extraction helper, the clock sysvar reuses handle_sysvar, and clones made only to read account metadata are now borrows.

Evidence

• Before: 167 tests pass, clippy clean.
  After: 167 tests pass, cargo clippy --all-features --all-targets and cargo +nightly fmt --check clean, and the crate builds with default features.
• Benches (simple_bench, max_perf, set_clock) show no difference beyond run-to-run noise. Two runs of the same code drifted by up to 5.5%.

Merge Danger

Door: two-way

Pure refactor, reverting is trivial.

Blast Radius: low

Things you might notice:

• Some log::error! messages in accounts_db are worded differently.
• persistence::save_to_file now serializes before it opens the file, so a failed serialization no longer leaves an empty file behind.