render buttons as neon tubes and rebuild the login page

The previous commit only swapped theme tokens, so buttons kept the solid
blue from arco.css: a-button fills with rgb(var(--primary-6)), which maps
to --arcoblue-6, not --color-primary. Bridge both naming families so no
Arco blue survives.

Style buttons as hollow tubes rather than filled blocks: transparent
fill, 1px cyan wall, inner glow plus two outer halos, and a glowing
label. Hover brightens the wall, active pinches the halo inward,
loading pulses, disabled cuts power entirely. Same treatment in red for
destructive actions, and hollow-line chips for inputs, tags, switches
and popups.

Rebuild LoginView to match the approved prototype: 32px masked grid,
scanline, IsometricWave, neon card edge, badge, probe status lamp, and
default-credential chips. Logic, API calls and lock/reset messaging are
unchanged.

packages/client/src/i18n/locales/en.ts

@@ -19,6 +19,14 @@ export default {
     lockResetHint: 'If this is your server, clear the login lock with:',
     defaultLoginResetHint: 'To reset the default admin password, run:',
     sessionExpired: 'Login expired. Please sign in again.',
+    probing: 'Probing server…',
+    online: 'Auth service online · password login available',
+    offline: 'Cannot reach the server · you can still try to log in',
+    showPassword: 'Show password',
+    hidePassword: 'Hide password',
+    fillDefaultCredentials: 'Fill in admin / 123456',
+    localDeploymentNote: 'Self-hosted · no telemetry · data never leaves this machine',
+    tokenHint: 'The token returned by POST /api/auth/login is stored in localStorage',
     accessDenied: 'You do not have permission to access this resource.',
     passwordMismatch: 'Passwords do not match',
     passwordTooShort: 'Password must be at least 6 characters',