Add config-driven glibc malloc_trim for long-lived Hermes processes:
- hermes_cli/mem_trim.py: trim_memory() with configurable cooldown,
RSS snapshot telemetry, and forced-trim INFO logging
- gateway/run.py: periodic trim in gateway housekeeping loop
- tui_gateway/server.py: trim in idle reaper (~every 5 min)
- tui_gateway/slash_worker.py: trim on turn boundary
- run_agent.py: force trim on agent close
- hermes_cli/config.py: context.memory_trim config section
(enabled, cooldown_seconds, log_every_n, info_log_min_delta_mb)
CSA tier-4 reviewed (4 rounds, 0 HIGH/MEDIUM/CRITICAL remaining).
Supersedes PR #63708 + #64591 with enhanced telemetry and gateway/slash_worker coverage.