feat(norms): hosts, containers and monitor response times are graded against their own normal (#5742)

Host CPU, memory and load per core, container CPU and memory, and every
monitor's response time learn a normal per hour (milestone 513, System 182).
A reading past its fixed cutoff but within its normal reads healthy and says
what is usual at this hour; one well out of it keeps its grade and is a
metric anomaly. Disk, a monitor down and an agent offline keep their cutoffs.

- Each normal's floor, the smallest departure that counts, is a setting:
  Settings -> Thresholds -> Normals (norms.floor.*). Defaults: host CPU 10
  points, host memory 5, load per core 10, container CPU 10 points of one
  core, container memory 5, monitor response 100 ms; Traefik's 2-point 4xx
  and 50 ms p95 floors move there from constants. learn_normal takes a
  floor function (floor_setting) read at each pass.
- learn_normal(parts=False): a host learns, its cores don't.
- Ingest records load_pct (load_1m / cores x 100), the figure pages grade.
- Shared grading: anomalies.against / graded, worst_reading(normals=),
  hosts' host_grades, docker usage(thresholds=, norms=), monitors'
  latency_grade. Applied to host vitals, the Hosts widget, MCP overview,
  Docker usage, and the monitor list, widget and page.
- The monitor and container pages list their anomalies.

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

docs/plugins/traefik.md

@@ -89,7 +89,7 @@ The full Traefik page at `/plugins/traefik/` reads top to bottom, for the time r
 
 A router is graded on its last 15 minutes against Settings → Thresholds. When a problem started is read from the router's history over the range.
 
-Once a router has 5 days of history, its 4xx share and p95 latency are judged against its own normal for that hour (see [Normals and anomalies](../architecture.md)) instead of the fixed cutoffs. One over the cutoff but within its normal is healthy, and the healthy table says it is usual for that router (an error-pages service that answers 4xx all day, a login wall's steady 401s). One out of its normal is a warning that says what is usual, and a metric anomaly to review; the Traefik page lists the routers' anomalies of the last 30 days. A 4xx share over fewer requests in the 15 minutes than Settings → Thresholds allows (30 by default) isn't judged at all. The 5xx share is a failure and always keeps its fixed cutoff. Latency is learned only from #5755's per-scrape figures, so its normal arrives 5 days after that release.
+Once a router has 5 days of history, its 4xx share and p95 latency are judged against its own normal for that hour (see [Normals and anomalies](../architecture.md)) instead of the fixed cutoffs. One over the cutoff but within its normal is healthy, and the healthy table says it is usual for that router (an error-pages service that answers 4xx all day, a login wall's steady 401s). One out of its normal is a warning that says what is usual, and a metric anomaly to review; the Traefik page lists the routers' anomalies of the last 30 days. How far out counts is set on Settings → Thresholds → Normals (2 points of 4xx share, 50 ms of p95 by default). A 4xx share over fewer requests in the 15 minutes than Settings → Thresholds allows (30 by default) isn't judged at all. The 5xx share is a failure and always keeps its fixed cutoff. Latency is learned only from #5755's per-scrape figures, so its normal arrives 5 days after that release.
 
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