- Single source for the approval-derived bound: public human_wait_ceiling()
in tools/approval.py; the gate's lock-timeout helper delegates to it
instead of re-deriving timeout + margin (was duplicated in two modules
and reached for a private _get_approval_timeout).
- Shared _clamped_window_seconds() for the close-time accrual and the
open-window read, so the two clamps are identical by construction.
- Gate __init__ grows session_key kwarg; tests construct via the real
constructor instead of mutating privates post-hoc.
- Gateway test resolves its pending approval via resolve_gateway_approval()
(the production /deny path) instead of hand-rolling queue-entry internals.
- Docstring accuracy: human_wait_seconds monotonicity caveat under cap
eviction; s/pre_tool_block/pre_tool_call/ hook name.
