feat: standardize input styling with tier system, add depth and admin features

- Define 4 input tier CSS classes (input-standard, input-search, input-embedded, input-danger)
  in globals.css, migrating ~50 inputs across ~28 component files to use them
- Add subtle border and inset shadow to solid input tiers for resting-state visibility
- Fix focus ring clipping in settings panel scroll container
- Fix phantom Tailwind tokens (border-border-primary, placeholder-txt-muted)
- Add admin user management panel, storage management, and account deletion utilities

packages/web/src/components/modals/UserSettings.tsx

@@ -83,7 +83,7 @@ export function UserSettingsModal() {
         </div>
 
         {/* Content */}
-        <div className="flex-1 min-w-0 overflow-y-auto scrollbar-thin">
+        <div className="flex-1 min-w-0 overflow-y-auto scrollbar-thin px-1">
           {tab === 'account' && <AccountPanel />}
           {tab === 'voice' && <VoicePanel />}
           {tab === 'privacy' && <PrivacyPanel />}