Add LDAP avatar photos, UX polish, and TDS component upgrades

- Add /api/avatar endpoint querying lldap for user jpegPhoto; disk cache
  with sentinel pattern avoids repeat LDAP hits for users without photos
- Add ldap3 dependency and ldap config block to config.json
- Wire lt-avatar img overlay in base.html with capture-phase error
  fallback (lt-avatar-img-err) to reveal initials when image is absent
- Fix lt-avatar CSS shim: position:relative + absolute inset on img
  (local base.css was missing these; added to style.css)
- Replace all empty-state paragraphs with proper lt-empty-state markup
  (icon + title + body) across index, suppressions, inspector, app.js
- Add lt-spinner--cyan next to refresh button; shows during refreshAll()
- Replace inspector panel-section-title with lt-divider throughout
- Add data-tooltip attributes to SFP DOM metrics, TX/RX/Carrier/Duplex/
  Auto-neg/Error labels in links.html and inspector panel
- Add tooltips to events table column headers (Sev, First Seen, Failures)
- Fix links.html host panel timestamp (was reading sample.updated which
  is always undefined; now uses data.updated)
- Fix UniFi status text casing (Online→ONLINE to match server render)
- Remove dead topo-status-* class manipulation from updateTopology()
- Always render alert-count-badge; toggle display:none when count is 0
- Fix double UniFi get_devices() call in monitor.py run loop
- Fix chip-critical animation (was using green pulse-glow; now red)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

requirements.txt

@@ -1,5 +1,6 @@
 flask>=2.2.0
 gunicorn>=20.1.0
+ldap3>=2.9
 pymysql>=1.1.0
 requests>=2.31.0
 urllib3>=2.0.0