feat(settings): add Hermes config dir override with data-driven dispatch

Adds a dedicated Hermes row to the directory-override settings so users
can point CC Switch at alternate Hermes config locations (e.g. a second
profile directory for work/personal split). `get_config_dir` on the
Rust side already supports hermes; this just wires up the frontend row.

Wiring it through `useDirectorySettings` revealed a scaling problem:
every supported app required five parallel ternary chains across
`computeDefaultConfigDir`, `updateDirectory`, `browseDirectory`,
`resetDirectory`, and `updateDirectoryState`. Replaces those with two
lookup tables (`APP_DIRECTORY_META`, `DIRECTORY_KEY_TO_SETTINGS_FIELD`)
so adding the next app is two entries, not fifteen edit sites.

Drive-by cleanup from the same touch:
* `resetAllDirectories` takes a `ResolvedAppDirectoryOverrides` object
  instead of five positional optional strings.
* `setResolvedDirs` returns the same reference when the sanitized
  value is unchanged, so no-op edits don't cascade renders.

Also lands all i18n updates for this series (`hermesConfigDir` and
placeholder, Memory section's enable/disable/toggleFailed copy, and
the reworded `schemaMigratedV12` warning) in zh/en/ja together.

tests/hooks/useSettings.test.tsx

@@ -455,13 +455,14 @@ describe("useSettings hook", () => {
     expect(settingsFormMock.syncLanguage).toHaveBeenCalledWith(
       settingsFormMock.initialLanguage,
     );
-    expect(directorySettingsMock.resetAllDirectories).toHaveBeenCalledWith(
-      "/server/claude",
-      undefined,
-      "/server/gemini",
-      "/server/opencode",
-      "/server/openclaw",
-    );
+    expect(directorySettingsMock.resetAllDirectories).toHaveBeenCalledWith({
+      claude: "/server/claude",
+      codex: undefined,
+      gemini: "/server/gemini",
+      opencode: "/server/opencode",
+      openclaw: "/server/openclaw",
+      hermes: undefined,
+    });
     expect(metadataMock.setRequiresRestart).toHaveBeenCalledWith(false);
   });