Remove Zig state-machine tests/fuzzer/workload/auditor orphaned by state_machine.zig removal

[devin-ai-integration]

Summary

ocam/src/state_machine.zig was replaced by the OCaml state_machine.ml, leaving the Zig files that exercised it orphaned and uncompilable (they all @import the deleted state_machine.zig). This PR deletes them plus the plumbing that referenced only them:

• Deleted: ocam/src/state_machine/workload.zig, ocam/src/state_machine/auditor.zig, ocam/src/state_machine_tests.zig, ocam/src/state_machine_fuzz.zig.
• unit_tests.zig: dropped _ = @import("state_machine.zig" | "state_machine_fuzz.zig" | "state_machine_tests.zig").
• fuzz_tests.zig: dropped the .state_machine fuzzer entry and its .state_machine => 10_000 smoke arm (the arm would otherwise name a non-existent enum tag). The .state_machine log scope is kept, since testing/state_machine.zig still uses it.
• scripts/cfo.zig: dropped state_machine from Fuzzer and weights so CFO doesn't schedule a fuzzer that no longer exists.
• tidy.zig: dropped the long-line exemption that matched only state_machine_tests.zig.

Not touched: testing/state_machine.zig (the synthetic VSR test state machine, a separate file) and the upstream submodule at path/to/tigerbeetle, which still has the full reference copies.

Owner please confirm: ocam/OCAML_REWRITE.md describes the copied Zig tree as a deliberately kept pinned copy / behavior oracle that is meant to be re-linked to the OCaml module later through a C-ABI adapter. If these specific test/fuzz/workload files should stay as part of that reference, close this PR. The originals are still in the path/to/tigerbeetle submodule and in git history.

Verification: dune build, dune runtest, dune build @bench and opam lint all pass. No OCaml files changed, so @fmt is unaffected. Zig is not installed and this Zig tree doesn't compile either before or after this change, so there is no Zig build to run.

Link to Devin session: https://app.devin.ai/sessions/d77673098fd7445ab2d932e7537252a7
Open in Devin Desktop: https://app.devin.ai/desktop/session/d77673098fd7445ab2d932e7537252a7?variant=devin
Requested by: @gpu004

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring