Add AT&T modem monitoring and device pages; replace Link Debug

Modem and WAN:
- Poll the BGW320 status pages read-only for light levels, PON and WAN
  state, with a WAN / Fiber panel, 7-day Rx trend, and alerts on WAN down,
  optical limits, and Rx drift
- Read WAN outages and Smart Power restarts from the UniFi system log,
  since outages can be over between 5 minute polls

Device pages:
- Add device search to the dashboard and a page per host, switch, router,
  AP, PDU, or modem
- Move all Link Debug data into expandable rows there; /links redirects
- Collect UDM ports and UniFi device details (firmware, load, WAN, outlets)
- Reorder the dashboard

Monitoring fixes:
- Alert when a configured host stops reporting: its series disappear
  rather than reporting down, so a dead host never raised an alert
- Alert on Prometheus outages instead of blanking the dashboard
- Treat a failed Pulse ping as unknown rather than host unreachable
- Stop new switch ports reporting lifetime bytes as one interval's rate
- Run database sessions in UTC: other server time zones shifted displayed
  ages and timed suppression expiries

Also log every avatar 404 reason, add a favicon, and correct the WAN link
labels (1G on Port 9, not 10G SFP+).

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

scripts/demo/capture.py

@@ -6,6 +6,7 @@ import asyncio
 import io
 import pathlib
 import sys
+from urllib.parse import quote
 
 from PIL import Image
 from playwright.async_api import async_playwright
@@ -81,18 +82,12 @@ async def shots():
         if hb:
             await pg.locator("#hosts-grid, .host-grid, .hosts-grid").first.screenshot(path=f"{OUT}/host-cards.png")
             print("host-cards ok")
-        await go(pg, "/links")
-        await pg.screenshot(path=f"{OUT}/link-debug.png")
-        names = await pg.evaluate("[...document.querySelectorAll('.link-host-name')].map(e=>e.textContent.trim())")
-        print("hosts", names)
-        for nm, fn in (
-            ("large1", "link-debug-sfp-warning"),
-            ("compute-storage-gpu-01", "link-debug-sfp"),
-            ("Pro 24 PoE", "link-debug-switch"),
-        ):
-            i = next((k for k, n in enumerate(names) if nm in n), None)
-            if i is not None:
-                await el(pg, ".link-host-panel", fn, i)
+        await go(pg, "/device/large1")
+        await pg.locator('.device-row-toggle[data-row="enp5s0"]').click()
+        await pg.wait_for_timeout(300)
+        await pg.screenshot(path=f"{OUT}/device-host.png", full_page=True)
+        await go(pg, "/device/" + quote("Pro 24 PoE"))
+        await pg.screenshot(path=f"{OUT}/device-switch.png", full_page=True)
         await go(pg, "/inspector")
         await pg.screenshot(path=f"{OUT}/inspector.png")
         await select_port(pg, "USW-Aggregation", 4)
@@ -133,7 +128,7 @@ async def gif():
         await snap(3, 600)
         await pg.mouse.wheel(0, 700)
         await snap(2, 600)
-        await go(pg, "/links", 4500)
+        await go(pg, "/device/large1", 4500)
         await snap(3)
         await pg.mouse.wheel(0, 500)
         await snap(2, 500)