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/commands/hermes.rs

@@ -40,12 +40,6 @@ pub fn get_hermes_live_provider(
     hermes_config::get_provider(&providerId).map_err(|e| e.to_string())
 }
 
-/// Scan config.yaml for known configuration hazards.
-#[tauri::command]
-pub fn scan_hermes_config_health() -> Result<Vec<hermes_config::HermesHealthWarning>, String> {
-    hermes_config::scan_hermes_config_health().map_err(|e| e.to_string())
-}
-
 // ============================================================================
 // Model Configuration Commands
 // ============================================================================