fix(docs): align slash-command and Docker references

[Tortugasaur]

Summary

• align the slash-command reference with the current CLI/gateway command surface, including /credits, /suggestions, /blueprint, and gateway-only /platform
• fix /suggestions behavior descriptions and mark /billing CLI-only in the command registry so generated gateway help no longer advertises an unsupported command
• refresh the zh-Hans Docker and environment-variable docs for the current s6-supervised dashboard/profile behavior and newly documented env vars

Verification

• python3 - <<'PY' ... introspection: confirmed /billing is no longer exposed in gateway help, /platform remains gateway-only, and CLI command lookups still include the expected surfaces
• python3 - <<'PY' ... manual /suggestions verification with a temporary HERMES_HOME: confirmed bare /suggestions lists pending items, catalog seeds curated automations, and clear only removes resolved records
• npm run build (website): passes and generates both build and build/zh-Hans; existing repo-wide broken-link / broken-anchor warnings remain, but the edited pages no longer add new failures to the build exit status
• git diff --check
• scripts/run_tests.sh tests/cron/test_suggestions.py tests/cron/test_blueprint_catalog.py tests/agent/test_credits_view.py (blocked in this worktree because the shared venv at /home/luigi/.hermes/hermes-agent/venv does not have pytest installed: /home/luigi/.hermes/hermes-agent/venv/bin/python: No module named pytest)

[teknium1]

Merged via PR #49944 (docs salvage cluster 2). Your commit was cherry-picked onto current main with your authorship preserved in git log — rebase-merged so it lands under your name. Thanks for the contribution!