Derive the env-var scrub lists from clap's bindings; SOCKET_NO_SOCKET_YML is missing from LOCAL_ARG_ENV_VARS #1837

[agent] Filed by the scheduled architecture audit (audit-cli-tests). Register: register comment.

Kind: refactor. Register ID: T03.

Problem

GLOBAL_ARG_ENV_VARS and LOCAL_ARG_ENV_VARS (args.rs L711-L761) are hand-kept copies of the env = "..." attributes on the clap structs. Three things read them:

• scrub_empty_env_vars;
• the hermetic test child builder (tests/common/hermetic.rs L95-L99);
• with_clean_socket_env.

They have drifted. scan --no-socket-yml binds SOCKET_NO_SOCKET_YML (scan/socket_yml_args.rs L17),`` but neither list names it. So a developer's ambient SOCKET_NO_SOCKET_YML=1 reaches every "hermetic" test child and silently disables socket.yml policy in `e2e_socket_yml_policy`.

The doc above the list (L739-L744) claims that "the invariant tests below parse every entry against its owning subcommand to keep this honest". But those tests iterate their own hand lists, BOOL_BINDINGS and VALUE_BINDINGS (args.rs L1697 and L1786), and global_arg_env_vars_includes_vendor_knobs (L1207) only checks that the const contains strings typed into it. More hand copies exist in tests/cli_parse_scan.rs (SCAN_ENV_VARS, L40-L55) and the other cli_parse_* files.

Proposed change

• Replace both consts with one function that walks crate::cli_command() and every subcommand's args, collecting Arg::get_env(). The global/local split, if still needed, comes from Arg::is_global_set().
• Point the hermetic builder, with_clean_socket_env and scrub_empty_env_vars at it.
• Delete the tautological global_arg_env_vars_includes_vendor_knobs.
• Generate BOOL_BINDINGS from the same walk, filtered on the parse_bool_flag value parser or kept as an explicit list asserted equal to the walk.

Size

args.rs, tests/common/hermetic.rs and the cli_parse_* helpers. About −80 / +30 lines.

Acceptance criteria

• A new test asserts that every env binding in cli_command() is scrubbed. It fails on today's main because SOCKET_NO_SOCKET_YML is missing.
• The existing parse tests stay green.
• With SOCKET_NO_SOCKET_YML=1 set in the outer environment, cargo test -p socket-patch-cli --test e2e_socket_yml_policy stays green.