Five test files and five evals scripts merged since this branch's base still import the
moved names via gateway.platforms.base. They work (base.py imports the names for its own
use) but the PR's invariant is that in-tree code imports from the defining module.
The salvaged helper was appended to the gateway/run.py facade; new behaviour
belongs in a topical sibling. agent/session_activity.py already owns the
activity-snapshot contract the three render sites read from, so the formatter
moves there as format_iteration_progress and the three call sites import it at
module level instead of late-importing the facade.
Tests trimmed to the salvage bar (<= 2 invariant tests per fix): one
parameterized contract on the helper (unbounded/None hide the ceiling, a real
budget keeps N/M) plus the contributor's end-to-end busy-ack test through the
real render path. The per-site heartbeat/timeout tests exercised the same
helper through mocks and are dropped; evals/gateway_status_render/
iteration_ceiling_ab.py drives all three real render sites with a real AIAgent
for before/after evidence (3 sentinel leaks on main -> 0).
Related: #103109 (same fix, same target module; credited in the PR),
#102845 (third render site, closed by its author in favour of #102817).
kshitijk4poor