Description

Redesigns the User Management page (/admin/users) for clarity and scale.
Part 2 of issue #553 (part 1 — profile page + avatar picker — merged in #573).

Changes:

• Avatars — each row now shows a UserAvatar (32 px) with an amber ring
  and shield badge for admins, reusing the component from feat: user profile page with avatar (account info, icon/image avatar, sign out) #573.

• Live search — a full-width search bar filters by username
  (case-insensitive, substring, trims whitespace). The counter shows
  N of M users while filtering and a ✕ Clear button resets it.

• Skeleton loading — replaces the plain "Loading…" text with 3 pulsing
  placeholder rows while the user list fetches.

• Empty state — when there are no users, shows a Users icon, a heading,
  and an Add user shortcut instead of a bare "No users found." message.

• No-match state — when search yields nothing, shows a friendly message
  with a Clear search link (no list renders at all).

• ConfirmDialog — new focus-trapped modal (web/components/ui/ConfirmDialog.tsx)
  replaces all three window.confirm() calls (delete, promote, demote).
  Cancel button takes initial focus so a stray Enter never fires a destructive
  action. Supports tone="danger" (red button) and a busyLabel while
  the request is in flight. Closes on Escape and overlay click.

• Header fix — Back link moved to its own row above the title

New files:

• web/components/ui/ConfirmDialog.tsx
• web/lib/admin-users.ts — pure filterUsersByQuery<T> function
• web/tests/admin-users-filter.test.ts — 5 node:test unit tests

Related Issues

• Closes [Feature Request]: User profile page (account + avatar) and a lighter Admin page #553 (part 2 — admin Users page)
• Depends on feat: user profile page with avatar (account info, icon/image avatar, sign out) #573 (UserAvatar component, already merged)

Module(s) Affected

• agents
• api
• config
• core
• knowledge
• logging
• services
• tools
• utils
• web (Frontend)
• docs (Documentation)
• scripts
• tests
• Other: ...

Checklist

• I have read and followed the contribution guidelines.
• My code follows the project's coding standards.
• I have run pre-commit run --all-files and fixed any issues.
• I have added relevant tests for my changes.
• I have updated the documentation (if necessary).
• My changes do not introduce any new security vulnerabilities.

Additional Notes

Tests: filterUsersByQuery is covered by 5 unit tests in
web/tests/admin-users-filter.test.ts (empty query, case-insensitive,
trim, non-latin/Cyrillic, no-match). npm run test:node → 147 passed.
ConfirmDialog and the page component are React — not testable in the
node:test harness; no Playwright e2e precedent exists in this repo for
admin pages.

Screenshots:

State	Light	Dark
Table
Search filter
No match
Confirm dialog
Empty state

Open to any feedback — if this doesn't fit the project's direction, no worries at all, happy to discuss and rework as needed.