Follow-up cleanups on top of the busy/idle readout (PR #50103):
- web_server.py /api/status reused the single drain-timeout resolver
hermes_cli.gateway._get_restart_drain_timeout() (HERMES_RESTART_DRAIN_TIMEOUT
env -> agent.restart_drain_timeout config -> default) instead of inlining a
third hand-rolled copy of that precedence chain. Also fixes a subtle
divergence: the inline copy used os.environ.get() so a set-but-empty env var
was treated as a value rather than falling through to config; the shared
resolver .strip()s and falls through correctly.
- Added gateway.status.parse_active_agents() and routed BOTH HTTP surfaces
(/api/status and /health/detailed) through it, so the exposed active_agents
field is consistently clamped non-negative. Previously /api/status clamped
while /health/detailed exposed the raw file value, diverging on a corrupt
count.
- Added TestParseActiveAgents covering the shared coercion contract.