Add local server state machine subprocess tests

[sdairs]

Summary

• add one table-driven, isolated subprocess suite for the local ClickHouse server state machine
• cover fresh, default, custom, omitted/explicit selection, exact-CWD, and explicit global project transitions
• assert exact output contracts, metadata, process liveness, data persistence/removal, telemetry isolation, and cleanup

Tests

• cargo test -p clickhousectl --test local_server_state_machine_test (3 runs, including concurrent runs)
• cargo test -p clickhousectl
• cargo test --workspace
• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings

Closes#479