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/AddDmMemberModal.tsx

@@ -97,7 +97,7 @@ export function AddDmMemberModal() {
           value={query}
           onChange={(e) => handleSearch(e.target.value)}
           placeholder="Search for a user..."
-          className="w-full px-3 py-2 bg-surface-input text-txt-primary placeholder-txt-tertiary/60 rounded-[4px] text-[14px] outline-none focus:ring-1 focus:ring-accent-primary"
+          className="input-search w-full py-2 text-[14px]"
           disabled={memberCount >= 10}
         />