Salvaged from PR #1573 by @eren-karakus0. Cherry-picked with authorship preserved.
Fixes#1143 — background process notifications resume after gateway restart.
Co-authored-by: Muhammet Eren Karakuş <erenkar950@gmail.com>
Extend subprocess env sanitization beyond provider credentials by blocking Hermes-managed tool, messaging, and related gateway runtime vars. Reuse a shared sanitizer in LocalEnvironment and ProcessRegistry so background and PTY processes honor the same blocklist and _HERMES_FORCE_ escape hatch. Add regression coverage for local env execution and process_registry spawning.
Cover model_tools, toolset_distributions, context_compressor,
prompt_caching, cronjob_tools, session_search, process_registry,
and cron/scheduler with 127 new test cases.
