feat(settings): configurable monitoring thresholds

Move the hardcoded warn/crit cutoffs into Settings -> Thresholds (DB-backed,
live, no restart). New thresholds.* keys + to_thresholds_cfg() + a
threshold_style(value, kind) jinja global that reads them; latency reuses the
existing ping good/warn keys, uptime is direction-aware (floors).

Replace the _macros metric_style/uptime_style macros (now removed) with the
global across Hosts-Overview, host_agent fleet + panel, Uptime/SLA widget, and
the ping page uptime column — all now honor the configured cutoffs. Uptime keeps
its green 'good' look when not degraded.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

steward/templates/_macros.html

@@ -17,24 +17,6 @@
 </nav>
 {%- endmacro %}
 
-{# Threshold emphasis for a numeric metric (CPU/mem/disk %, etc).
-   Returns an inline-style fragment to drop into a span's style="": amber +
-   semibold at >= warn, red + bold at >= crit, empty (inherit) when the value
-   is normal or None. This makes the FAILING METRIC ITSELF stand out — not just
-   the status dot. Defaults suit percentage gauges (warn 80 / crit 90); pass
-   explicit warn/crit for other scales. Keep thresholds here so they live in one
-   place rather than hardcoded per template. #}
-{% macro metric_style(value, warn=80, crit=90) -%}
-{%- if value is not none and value >= crit -%}color:var(--red);font-weight:700;
-{%- elif value is not none and value >= warn -%}color:var(--yellow);font-weight:600;
-{%- endif -%}
-{%- endmacro %}
-
-{# Inverted emphasis for "higher is better" metrics like uptime %: amber below
-   `warn`, red below `crit`. The mirror of metric_style — same one-place-for-
-   thresholds discipline, opposite direction. Defaults suit SLA percentages. #}
-{% macro uptime_style(value, warn=99.0, crit=95.0) -%}
-{%- if value is not none and value < crit -%}color:var(--red);font-weight:700;
-{%- elif value is not none and value < warn -%}color:var(--yellow);font-weight:600;
-{%- endif -%}
-{%- endmacro %}
+{# Metric threshold coloring moved to the `threshold_style(value, kind)` jinja
+   global (steward/core/settings.py + app.py), which reads operator-configurable
+   cutoffs from Settings → Thresholds. Call it as threshold_style(v, 'cpu'). #}

steward/templates/hosts/overview_widget.html

@@ -1,7 +1,6 @@
 {# Unified Hosts widget — monitor status + agent glance per host, links to the hub.
    Name sits on its own line (never truncated); its data wraps beneath it, grouped
    under the host. Prefer vertical growth over cramming a row. #}
-{% from "_macros.html" import metric_style, uptime_style %}
 {% if hosts %}
 <div class="host-blocks">
   {% for host in hosts %}
@@ -27,15 +26,15 @@
     <div style="display:flex;flex-wrap:wrap;gap:0.25rem 0.9rem;margin-top:0.25rem;padding-left:1.1rem;
                 font-variant-numeric:tabular-nums;color:var(--text-muted);font-size:0.75rem;">
       {% if host.ping_enabled and ping and ping.response_time_ms is not none %}
-      <span title="Ping latency" style="{{ metric_style(ping.response_time_ms, warn=100, crit=250) }}"><span style="color:var(--text-dim);">ping</span> {{ "%.0f"|format(ping.response_time_ms) }}ms</span>
+      <span title="Ping latency" style="{{ threshold_style(ping.response_time_ms, 'latency') }}"><span style="color:var(--text-dim);">ping</span> {{ "%.0f"|format(ping.response_time_ms) }}ms</span>
       {% endif %}
       {% if ut.get('24h') is not none %}
-      <span title="Uptime 24h" style="{{ uptime_style(ut['24h']) }}"><span style="color:var(--text-dim);">24h</span> {{ "%.1f"|format(ut['24h']) }}%</span>
+      <span title="Uptime 24h" style="{{ threshold_style(ut['24h'], 'uptime') }}"><span style="color:var(--text-dim);">24h</span> {{ "%.1f"|format(ut['24h']) }}%</span>
       {% endif %}
       {% if a %}
-      {% if a.get('cpu_pct') is not none %}<span title="CPU — value + last-hour trend" style="display:inline-flex;align-items:center;gap:0.3rem;{{ metric_style(a.cpu_pct) }}"><span style="color:var(--text-dim);">cpu</span> {{ "%.0f"|format(a.cpu_pct) }}%{% if spark %}<span style="line-height:0;opacity:0.85;">{{ spark | safe }}</span>{% endif %}</span>{% endif %}
-      {% if a.get('mem_used_pct') is not none %}<span title="Memory" style="{{ metric_style(a.mem_used_pct) }}"><span style="color:var(--text-dim);">mem</span> {{ "%.0f"|format(a.mem_used_pct) }}%</span>{% endif %}
-      {% if a.get('disk_root') is not none %}<span title="Root filesystem (/)" style="{{ metric_style(a.disk_root) }}"><span style="color:var(--text-dim);">disk /</span> {{ "%.0f"|format(a.disk_root) }}%</span>{% endif %}
+      {% if a.get('cpu_pct') is not none %}<span title="CPU — value + last-hour trend" style="display:inline-flex;align-items:center;gap:0.3rem;{{ threshold_style(a.cpu_pct, 'cpu') }}"><span style="color:var(--text-dim);">cpu</span> {{ "%.0f"|format(a.cpu_pct) }}%{% if spark %}<span style="line-height:0;opacity:0.85;">{{ spark | safe }}</span>{% endif %}</span>{% endif %}
+      {% if a.get('mem_used_pct') is not none %}<span title="Memory" style="{{ threshold_style(a.mem_used_pct, 'mem') }}"><span style="color:var(--text-dim);">mem</span> {{ "%.0f"|format(a.mem_used_pct) }}%</span>{% endif %}
+      {% if a.get('disk_root') is not none %}<span title="Root filesystem (/)" style="{{ threshold_style(a.disk_root, 'disk') }}"><span style="color:var(--text-dim);">disk /</span> {{ "%.0f"|format(a.disk_root) }}%</span>{% endif %}
       {% if not a.fresh %}<span title="Agent data is stale" style="color:var(--yellow);">stale</span>{% endif %}
       {% else %}
       <span style="color:var(--text-dim);" title="No agent reporting">no agent</span>

steward/templates/hosts/uptime_widget.html

@@ -26,14 +26,11 @@
     <span style="text-align:center;font-family:ui-monospace,monospace;font-size:0.78rem;">
       {% if pct is none %}
         <span style="color:var(--text-dim);">—</span>
-      {% elif pct >= 99.9 %}
-        <span style="color:var(--green);">{{ "%.1f"|format(pct) }}%</span>
-      {% elif pct >= 99 %}
-        <span style="color:var(--yellow);">{{ "%.1f"|format(pct) }}%</span>
-      {% elif pct >= 95 %}
-        <span style="color:var(--orange);">{{ "%.1f"|format(pct) }}%</span>
       {% else %}
-        <span style="color:var(--red);">{{ "%.1f"|format(pct) }}%</span>
+        {# Configurable uptime thresholds (Settings → Thresholds); a normal value
+           (no degraded style) stays green to read as healthy at a glance. #}
+        {% set us = threshold_style(pct, 'uptime') %}
+        <span style="{{ us if us else 'color:var(--green);' }}">{{ "%.1f"|format(pct) }}%</span>
       {% endif %}
     </span>
     {% endfor %}

steward/templates/ping/rows.html

@@ -54,11 +54,8 @@
   </div>
   {% if uptime_pcts is defined %}
   {% set pct = uptime_pcts.get(host.id) %}
-  <div style="min-width:4.5rem;text-align:right;font-size:0.78rem;font-variant-numeric:tabular-nums;color:
-    {% if pct is none %}var(--text-dim)
-    {% elif pct >= 99 %}var(--green)
-    {% elif pct >= 95 %}var(--yellow)
-    {% else %}var(--red){% endif %};">
+  {% set us = threshold_style(pct, 'uptime') if pct is not none else 'color:var(--text-dim);' %}
+  <div style="min-width:4.5rem;text-align:right;font-size:0.78rem;font-variant-numeric:tabular-nums;{{ us if us else 'color:var(--green);' }}">
     {% if pct is not none %}{{ "%.1f"|format(pct) }}%{% else %}—{% endif %}
     <span style="color:var(--text-dim);font-size:0.7rem;margin-left:0.15rem;">{{ range_key }}</span>
   </div>

steward/templates/settings/_tabs.html

@@ -3,6 +3,7 @@
 <div style="display:flex;gap:0;border-bottom:1px solid var(--border-mid);margin-bottom:1.5rem;">
   {% set tabs = [
     ("general",       "General",        "/settings/general/"),
+    ("thresholds",    "Thresholds",     "/settings/thresholds/"),
     ("notifications", "Notifications",  "/settings/notifications/"),
     ("reports",       "Reports",        "/settings/reports/"),
     ("auth",          "Auth",           "/settings/auth/"),

steward/templates/settings/thresholds.html

@@ -0,0 +1,50 @@
+{# steward/templates/settings/thresholds.html — tunable degraded/critical cutoffs #}
+{% extends "base.html" %}
+{% block title %}Settings — Thresholds — Steward{% endblock %}
+{% block content %}
+{% set active_tab = "thresholds" %}
+{% include "settings/_tabs.html" %}
+
+{% macro pair(label, warn_field, warn_key, crit_field, crit_key, unit, hint, step="1") %}
+<div class="form-group" style="margin-bottom:1.1rem;">
+  <label>{{ label }} <span style="color:var(--text-muted);font-size:0.8rem;">({{ unit }})</span></label>
+  <div style="display:flex;gap:1.25rem;flex-wrap:wrap;margin-top:0.25rem;">
+    <span style="display:flex;align-items:center;gap:0.4rem;">
+      <span style="color:var(--yellow);font-size:0.8rem;font-weight:600;">warn</span>
+      <input type="number" name="{{ warn_field }}" step="{{ step }}"
+             value="{{ settings[warn_key] }}" style="max-width:110px;">
+    </span>
+    <span style="display:flex;align-items:center;gap:0.4rem;">
+      <span style="color:var(--red);font-size:0.8rem;font-weight:600;">crit</span>
+      <input type="number" name="{{ crit_field }}" step="{{ step }}"
+             value="{{ settings[crit_key] }}" style="max-width:110px;">
+    </span>
+  </div>
+  {% if hint %}<div style="font-size:0.78rem;color:var(--text-muted);margin-top:0.3rem;">{{ hint }}</div>{% endif %}
+</div>
+{% endmacro %}
+
+<form method="post" action="/settings/thresholds/">
+<div class="card" style="max-width:640px;">
+  <h2 class="section-title" style="margin-bottom:0.5rem;">Monitoring thresholds</h2>
+  <p style="font-size:0.82rem;color:var(--text-muted);margin-bottom:1.25rem;">
+    Values at or beyond <span style="color:var(--yellow);">warn</span> show amber; at or beyond
+    <span style="color:var(--red);">crit</span> show red — across dashboard widgets and host views.
+    Higher is worse for everything except uptime, where the cutoffs are floors.
+  </p>
+
+  {{ pair("CPU usage",    "cpu_warn",  "thresholds.cpu_warn",  "cpu_crit",  "thresholds.cpu_crit",  "%", "Average CPU utilization per host.") }}
+  {{ pair("Memory usage", "mem_warn",  "thresholds.mem_warn",  "mem_crit",  "thresholds.mem_crit",  "%", "Memory in use per host.") }}
+  {{ pair("Disk usage",   "disk_warn", "thresholds.disk_warn", "disk_crit", "thresholds.disk_crit", "%", "Filesystem usage.") }}
+  {{ pair("Load",         "load_warn", "thresholds.load_warn", "load_crit", "thresholds.load_crit", "% per core", "Load average normalized by core count (100% = one full core per core).") }}
+  {{ pair("Temperature",  "temp_warn", "thresholds.temp_warn", "temp_crit", "thresholds.temp_crit", "°C", "Hottest reported sensor per host.") }}
+  {{ pair("Ping latency", "latency_warn", "ping.threshold.good_ms", "latency_crit", "ping.threshold.warn_ms", "ms", "Round-trip time. Shared with the Ping widget's good/warn colouring.") }}
+  {{ pair("Uptime / SLA", "uptime_warn", "thresholds.uptime_warn", "uptime_crit", "thresholds.uptime_crit", "%", "Lower is worse — amber below warn, red below crit.", step="0.1") }}
+</div>
+
+<div style="margin-top:1rem;display:flex;align-items:center;gap:1rem;">
+  <button type="submit" class="btn">Save</button>
+  <span style="font-size:0.82rem;color:var(--text-muted);">Takes effect immediately — no restart.</span>
+</div>
+</form>
+{% endblock %}