feat(plugins): Traefik problems first, UniFi/SNMP/fleet on shared shapes, audit names its entities, templates on tokens (#5126)

Traefik: routers are graded from their latest scrape (router_state: crit on
any real 5xx share, warn on p95 past the latency critical cutoff or a high
4xx share). Failing and slow routers lead as cards that say why; healthy
ones fold into one table that stays open or shut across polls. Proxy
counts are stat tiles; certificates are graded by Settings -> Thresholds
(tls_days).

UniFi: WAN health is a stat strip (latency graded by the thresholds),
devices carry status dots, event categories and firewall actions are
badges, the alarm count reuses .count-badge (renamed from .nav-count).
SNMP: each device wears a status badge and its readings are stat tiles.

Agent fleet: the table comes first, with a Status column (Reporting /
Silent / Never reported, by the host page's stale_after_seconds), silent
agents first, hosts linked, last seen as |ago.

Audit: entries name their entity (one query per type, steward/audit/
service.py) and link it; something deleted since keeps the name its entry
recorded and says "(deleted)".

Tokens: charts read colours through chart-colors.js (stewardColor resolves
a token to the rgb the browser computed; Chart.js defaults take the page's
text and border colours), so host, history, Traefik and SNMP charts drop
their hex. Template hex colours reach 0 (HEX_CEILING = 0), the last rgba
pills go, and heavy weights (600/700/bold, 60 of them) become 500, the
house pair being 400/500; a guard keeps templates there.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/core/test_alerts_page.py

@@ -121,7 +121,7 @@ async def test_the_sidebar_counts_alerts_needing_attention(app, monkeypatch):
     async with app.test_request_context("/alerts/"):
         session["user_id"], session["user_role"] = "u1", "viewer"
         page = await render_template("alerts/list.html", active=[], rules=[], operators=[])
-    assert '<span class="nav-count" title="3 alerts need attention">3</span>' in page
+    assert '<span class="count-badge" title="3 alerts need attention">3</span>' in page
 
 
 async def test_no_count_for_a_fragment_or_a_logged_out_page(app, monkeypatch):
@@ -131,4 +131,4 @@ async def test_no_count_for_a_fragment_or_a_logged_out_page(app, monkeypatch):
         fragment = await render_template("alerts/list.html", active=[], rules=[], operators=[])
     async with app.test_request_context("/alerts/"):
         logged_out = await render_template("alerts/list.html", active=[], rules=[], operators=[])
-    assert "nav-count" not in fragment and "nav-count" not in logged_out
+    assert "count-badge" not in fragment and "count-badge" not in logged_out