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/architecture.md

@@ -111,6 +111,22 @@ Every minute, `metric_anomalies` averages each learned key's last 15 minutes and
 - Learning skips every hour an occurrence covers unless its anomaly was marked `normal`, so a new level is never learned without review.
 - `data_cleanup` prunes reviewed and lapsed rows at `data.retention_days`; a row still to review is never pruned.
 
+What learns a normal, and the floor each departure must clear (Settings → Thresholds → Normals, `norms.floor.*`; a floor may be a function, `floor_setting()`, read at each pass):
+
+| Kind | Metric | Floor (default) |
+|---|---|---|
+| Host CPU | `host_agent` / `cpu_pct` | 10 points |
+| Host memory | `host_agent` / `mem_used_pct` | 5 points |
+| Host load per core | `host_agent` / `load_pct` (load_1m ÷ cores × 100, recorded at ingest) | 10 points |
+| Container CPU | `docker` / `cpu_pct` (100% is one core) | 10 points of one core |
+| Container memory | `docker` / `mem_pct` (of its limit, or of host RAM when it has none) | 5 points |
+| Monitor response time | `<type>` / `response_ms` | 100 ms |
+| Router 4xx share, p95 | `traefik` / `error_rate_4xx_pct`, `latency_p95_ms` | 2 points, 50 ms |
+
+Host metrics learn with `parts=False`: the host learns, its cores (`<host>:core<N>`) don't. Disk space, a monitor that is down, an agent gone quiet and a router's 5xx share are failures and keep their fixed cutoffs.
+
+Pages grade by the normal through `anomalies.graded()` (hosts' `host_grades` and `worst_reading(normals=)`, `docker.service.usage(thresholds=, norms=)`, `monitors.service.latency_grade`): a reading past its cutoff but within its normal reads healthy and says what is usual at this hour. The host, monitor, container and Traefik pages list their anomalies with `_anomaly_card.html`.
+
 ---
 
 ## Database Session Pattern

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.
 
 ---