Phase 002: rebrand to hermes-ui and consolidate i18n to zh/en

Removes the ekko / hermes-web-ui branding from the whole tree and drops
eight locale files, so the project presents one name and one language pair.

Data compatibility is deliberate, not accidental: DB filenames, the JWT
audience, and skill manifest ownership all still recognise their pre-rename
values so existing deployments under ~/.hermes-web-ui keep working without a
re-login or a re-injection.

scripts/harness-check.mjs now scans for the legacy strings and fails the
build on any new occurrence, with an explicit allow-list (and reasons) for
the compatibility paths that must keep them.

tests/server/user-auth.test.ts

@@ -337,7 +337,7 @@ describe('user auth tables and middleware', () => {
       username: 'admin',
       role: 'super_admin',
       type: 'access',
-      aud: 'hermes-web-ui',
+      aud: 'hermes-ui',
       iat: 1,
       exp: 3601,
     })