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/login-limiter.test.ts

@@ -9,7 +9,7 @@ async function loadLimiter() {
   }))
   vi.doMock('fs', () => ({ writeFileSync: vi.fn() }))
   vi.doMock('../../packages/server/src/config', () => ({
-    config: { appHome: '/tmp/hermes-web-ui-test' },
+    config: { appHome: '/tmp/hermes-ui-test' },
   }))
   return import('../../packages/server/src/services/login-limiter')
 }