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/SpaceSettings.tsx

@@ -116,7 +116,7 @@ function DiscoveryPanel({ spaceId }: { spaceId: string }) {
             onChange={(e) => setDescription(e.target.value.slice(0, 200))}
             placeholder="A short description for the Explore page..."
             rows={3}
-            className="w-full px-3 py-2 bg-surface-input rounded text-sm text-txt-primary outline-none focus:ring-1 focus:ring-accent-primary resize-none placeholder:text-txt-tertiary"
+            className="input-standard w-full resize-none"
           />
           <div className="text-[11px] text-txt-tertiary text-right">{description.length}/200</div>
         </div>