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/types.ts

@@ -589,17 +589,6 @@ export interface HermesModelConfig {
   [key: string]: unknown;
 }
 
-export interface HermesHealthWarning {
-  code: string;
-  message: string;
-  path?: string;
-}
-
-export interface HermesWriteOutcome {
-  backupPath?: string;
-  warnings: HermesHealthWarning[];
-}
-
 export type HermesMemoryKind = "memory" | "user";
 
 export interface HermesMemoryLimits {