Add read-only external Yomitan profile support

- add `yomitan.externalProfilePath` config and default/template wiring
- load Yomitan from an external Electron profile/session when configured
- disable SubMiner Yomitan writes/settings UI in external-profile mode and update docs/tests

src/config/definitions/options-integrations.ts

@@ -211,6 +211,13 @@ export function buildIntegrationConfigOptionRegistry(
       description:
         'Open the Voiced by section by default in character dictionary glossary entries.',
     },
+    {
+      path: 'yomitan.externalProfilePath',
+      kind: 'string',
+      defaultValue: defaultConfig.yomitan.externalProfilePath,
+      description:
+        'Optional external Yomitan Electron profile path to use in read-only mode for shared dictionaries/settings.',
+    },
     {
       path: 'jellyfin.enabled',
       kind: 'boolean',