refactor(hermes): drop config health check scanner

The Hermes config.yaml schema has stabilized and users have migrated to
the current provider fields, so the value of scanning for model.provider
dangling references, custom_providers shape errors, v12 migration residue
etc. no longer justifies the maintenance surface — and the scan produces
false positives when users keep some providers under Hermes' v12+
providers: dict (Hermes' runtime merges both shapes, but CC Switch's
scanner only looked at the list form).

Removes the whole HermesHealthWarning type, scan_hermes_config_health
command, HermesHealthBanner React component, useHermesHealth hook,
warnings field on HermesWriteOutcome, and the three helper functions
(yaml_as_non_empty_str, collect_mapping_string_keys, hermes_warning)
that only served the scanner. Drops the matching i18n keys in
zh/en/ja and the fixInWebUI button label that only the banner used.

src-tauri/src/lib.rs

@@ -1264,7 +1264,6 @@ pub fn run() {
             commands::import_hermes_providers_from_live,
             commands::get_hermes_live_provider_ids,
             commands::get_hermes_live_provider,
-            commands::scan_hermes_config_health,
             commands::get_hermes_model_config,
             commands::open_hermes_web_ui,
             commands::launch_hermes_dashboard,