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/InviteModal.tsx

@@ -67,7 +67,7 @@ export function InviteModal() {
           type="text"
           value={isLoading ? 'Generating...' : inviteUrl}
           readOnly
-          className="invite-code-input flex-1 px-3 py-2 bg-surface-input rounded text-txt-primary outline-none font-mono text-xs"
+          className="input-standard invite-code-input flex-1 font-mono text-xs"
         />
         <button
           onClick={handleCopy}