`hermes tools` -> "All Platforms" took ~14s to render the checklist
because building the toolset labels called `get_nous_auth_status()` ~31x
transitively (`_toolset_has_keys` -> `_visible_providers` ->
`get_nous_subscription_features` -> `managed_nous_tools_enabled`).
Each call did a synchronous OAuth refresh POST to
portal.nousresearch.com (~350ms even on the failure path), so one menu
paint burned >13s of HTTP and 31 single-use Nous refresh tokens.
Secondary hot spot: every `get_env_value()` re-read and re-sanitised
the entire .env file. 116 reads with O(lines x known-keys) scanning
added ~300ms of CPU per render.
Fix is two process-level caches, both mtime-keyed so login/logout/edit
invalidate naturally:
* `hermes_cli/auth.py`: memoise `get_nous_auth_status()` for 15s keyed
on auth.json mtime. Splits `_compute_nous_auth_status()` as the
uncached impl. Adds `invalidate_nous_auth_status_cache()`.
* `hermes_cli/config.py`: memoise `load_env()` keyed on .env
(path, mtime, size). Adds `invalidate_env_cache()`, wired into
`save_env_value`, `remove_env_value`, and the sanitize-on-load
writer so writers don't return stale dicts on same-second writes.
Before/after on Teknium's box (real HERMES_HOME, no Nous login):
* "All Platforms" cold path: ~13,874ms -> ~691ms label-build
* Warm re-open within the same process: ~122ms -> ~17ms
Side benefit: stops burning a Nous refresh token on every menu paint,
which was risking the portal's reuse-detection revocation logic.
