printers: low-toner alerts with configurable thresholds + support-team routing

Poll Zabbix for toner levels on a schedule and email/webhook on a downward
crossing. Warning fires at or below the warning threshold (default 5%),
critical at the critical threshold (default 0%); both thresholds are settings.
State lives in printersupplyalerts so an alert fires once per crossing and
re-arms after a refill.

Recipients mirror the printedparts pattern: plugin-scoped shopdb users +
roles + free-text emails (falling back to the site alert_recipients), and a
chosen support team's webhook (falling back to the site alert_webhook_url).

- PrinterSupplyAlert model + migration printers0002supplyalerts
- alerttier(remaining, warning, critical) + check_supplies poller
- flask printers check-toner-alerts CLI (run via scheduled task/cron)
- printers alert settings + Low-Toner Alerts settings page
- 7 tests: tier boundaries, once-per-crossing + re-arm, toner-only scope,
  custom thresholds, support-team webhook routing

plugins/printers/frontend/routes.js

@@ -20,6 +20,12 @@ export default [
     component: () => import('./views/ZabbixSettings.vue'),
     meta: { requiresAuth: true, requiresAdmin: true, plugin: 'printers' }
   },
+  {
+    path: 'settings/printer-alerts',
+    name: 'printer-alerts',
+    component: () => import('./views/PrinterAlertsSettings.vue'),
+    meta: { requiresAuth: true, requiresAdmin: true, plugin: 'printers' }
+  },
   {
     path: 'printers',
     name: 'printers',

plugins/printers/frontend/views/PrinterAlertsSettings.vue

@@ -0,0 +1,192 @@
+<template>
+  <div>
+    <div class="page-header">
+      <h2>Low-Toner Alerts</h2>
+    </div>
+
+    <div class="card form-card">
+      <div v-if="message" class="settings-success">{{ message }}</div>
+      <div v-if="error" class="error-message">{{ error }}</div>
+
+      <p class="field-hint">
+        A scheduled poll checks Zabbix toner levels. A warning email fires when
+        a toner crosses to the warning threshold or below, a critical email at
+        the critical threshold. Alerts fire once per crossing; a refill re-arms
+        them.
+      </p>
+
+      <div class="form-row">
+        <div class="form-group">
+          <label>Warning threshold (% remaining)</label>
+          <input v-model.number="values.printers_alert_warning_threshold"
+                 type="number" min="0" max="100" class="form-control" />
+        </div>
+        <div class="form-group">
+          <label>Critical threshold (% remaining)</label>
+          <input v-model.number="values.printers_alert_critical_threshold"
+                 type="number" min="0" max="100" class="form-control" />
+        </div>
+      </div>
+
+      <div class="form-group">
+        <label>Alert shopdb users</label>
+        <div class="user-picker">
+          <label v-for="candidate in users" :key="candidate.userid" class="user-row">
+            <input type="checkbox" :value="String(candidate.userid)"
+                   v-model="selectedUserids" />
+            <span>{{ candidate.username }}</span>
+            <span class="user-email">{{ candidate.email }}</span>
+          </label>
+          <p v-if="users.length === 0" class="field-hint">No users loaded</p>
+        </div>
+        <p class="field-hint">
+          Selected users receive low-toner alerts at their account email.
+        </p>
+      </div>
+
+      <div class="form-group">
+        <label>Alert roles</label>
+        <div class="user-picker">
+          <label v-for="role in roles" :key="role.roleid" class="user-row">
+            <input type="checkbox" :value="String(role.roleid)"
+                   v-model="selectedRoleids" />
+            <span>{{ role.rolename }}</span>
+            <span class="user-email">{{ role.description }}</span>
+          </label>
+          <p v-if="roles.length === 0" class="field-hint">No roles loaded</p>
+        </div>
+        <p class="field-hint">
+          Every active member of a selected role receives low-toner alerts.
+        </p>
+      </div>
+
+      <div class="form-group">
+        <label>Additional alert emails</label>
+        <input v-model="values.printers_alert_email" type="text"
+               class="form-control" placeholder="print-team@example.com, lead@example.com" />
+        <p class="field-hint">
+          Comma-separated. Empty uses the site-wide alert recipients
+          (Settings &gt; System &gt; Email).
+        </p>
+      </div>
+
+      <div class="form-group">
+        <label>Alert support team (Teams webhook)</label>
+        <select v-model="values.printers_alert_supportteamid" class="form-control">
+          <option value="">Site default webhook</option>
+          <option v-for="team in supportTeams" :key="team.supportteamid" :value="String(team.supportteamid)">
+            {{ team.teamname }}{{ team.webhookurl ? '' : ' (no webhook set)' }}
+          </option>
+        </select>
+        <p class="field-hint">
+          Low-toner alerts post to this team's webhook (set on Settings &gt;
+          Support Teams). Empty uses the site-wide alert webhook.
+        </p>
+      </div>
+
+      <button class="btn btn-primary" :disabled="saving" @click="save">
+        {{ saving ? 'Saving...' : 'Save' }}
+      </button>
+    </div>
+  </div>
+</template>
+
+<script setup>
+import { ref, onMounted } from 'vue'
+import { settingsApi, usersApi, supportteamsApi } from '@/api'
+
+const KEYS = [
+  'printers_alert_email',
+  'printers_alert_userids',
+  'printers_alert_roleids',
+  'printers_alert_supportteamid',
+  'printers_alert_warning_threshold',
+  'printers_alert_critical_threshold'
+]
+
+const values = ref({
+  printers_alert_email: '',
+  printers_alert_userids: '',
+  printers_alert_roleids: '',
+  printers_alert_supportteamid: '',
+  printers_alert_warning_threshold: 5,
+  printers_alert_critical_threshold: 0
+})
+const supportTeams = ref([])
+const users = ref([])
+const selectedUserids = ref([])
+const roles = ref([])
+const selectedRoleids = ref([])
+const saving = ref(false)
+const message = ref('')
+const error = ref('')
+
+onMounted(async () => {
+  try {
+    const response = await settingsApi.list({ category: 'printers' })
+    const rows = response.data.data || []
+    for (const row of rows) {
+      if (KEYS.includes(row.key)) values.value[row.key] = row.value
+    }
+    values.value.printers_alert_warning_threshold =
+      parseInt(values.value.printers_alert_warning_threshold, 10) || 0
+    values.value.printers_alert_critical_threshold =
+      parseInt(values.value.printers_alert_critical_threshold, 10) || 0
+    selectedUserids.value = (values.value.printers_alert_userids || '')
+      .split(',').map(id => id.trim()).filter(Boolean)
+    const usersResponse = await usersApi.list()
+    users.value = (usersResponse.data.data || []).filter(
+      candidate => candidate.isactive && candidate.email)
+    selectedRoleids.value = (values.value.printers_alert_roleids || '')
+      .split(',').map(id => id.trim()).filter(Boolean)
+    const rolesResponse = await usersApi.roles.list()
+    roles.value = rolesResponse.data.data || []
+    const teamsResponse = await supportteamsApi.list()
+    supportTeams.value = teamsResponse.data.data || []
+  } catch (loadError) {
+    error.value = 'Could not load settings'
+    console.error(loadError)
+  }
+})
+
+async function save() {
+  saving.value = true
+  message.value = ''
+  error.value = ''
+  try {
+    values.value.printers_alert_userids = selectedUserids.value.join(',')
+    values.value.printers_alert_roleids = selectedRoleids.value.join(',')
+    for (const key of KEYS) {
+      await settingsApi.update(key, String(values.value[key] ?? ''))
+    }
+    message.value = 'Settings saved'
+  } catch (saveError) {
+    error.value = saveError.response?.data?.data?.error?.message || 'Save failed'
+  } finally {
+    saving.value = false
+  }
+}
+</script>
+
+<style scoped>
+.field-hint { color: var(--text-light); font-size: 0.85rem; margin-top: 0.25rem; }
+.form-row { display: flex; gap: 1rem; }
+.form-row .form-group { flex: 1; }
+.user-picker {
+  max-height: 12rem;
+  overflow-y: auto;
+  border: 1px solid var(--border);
+  border-radius: 0.35rem;
+  padding: 0.5rem;
+  display: flex;
+  flex-direction: column;
+  gap: 0.35rem;
+}
+.user-row {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  cursor: pointer;
+}
+.user-email { color: var(--text-light); font-size: 0.85rem; }
+</style>