Cardano Updates

fix(logging): unify stderr and stdout handling in helpers

Updated `run_detached_command` to redirect stderr to stdout for consistent
logging. Simplified `cardano_cli_log` in common.sh by removing retry logic
and direct stderr capture, now invoking `cardano-cli` directly and returning
its exit code. This streamlines command execution and log output.

feat(config): add TraceOptions to submit-api configs

Added the "TraceOptions" section to the submit-api-config.json files for
conway_fast, conway_slow, and mainnet_fast scripts. This enables the new
tracing system while keeping the old configuration for older version of
submit-api that doesn't support the new tracing system yet.

refactor(scripts): unify truthy checks with is_truthy helper

Replaced manual environment variable checks with the new is_truthy function
across common-start-fast, common-start-slow, and common.sh scripts. This
ensures consistent handling of boolean-like environment variables such as
ENABLE_LEGACY, MIXED_P2P, NO_CC, DRY_RUN, and SMASH. The is_truthy helper
now supports common true values and improves code readability and
maintainability.

feat(config): add ENABLE_EXPERIMENTAL option to testnet configs

Added ENABLE_EXPERIMENTAL to the environment variable descriptions in
testnet.json files for conway_fast, conway_slow, and mainnet_fast. This
option enables experimental features in the local cluster when set.

feat(config): support ENABLE_EXPERIMENTAL for ExperimentalHardForksEn…

Allow setting of `ExperimentalHardForksEnabled` when ENABLE_EXPERIMENTAL is truthy,
regardless of protocol version.

Adds is_truthy helper for flexible checks.