Add email sending (service + 3 flows) and a general asset label generator

Email: a stdlib SMTP mailer (settings-first config, graceful no-op when
unconfigured), a test-email endpoint wired to the Email settings page,
forced first-login password change (users.mustchangepassword, migration
7d23, /change-password flow), new-user welcome mail, and on-demand
report/alert delivery (POST /api/reports/email + Email Report buttons)
with an external-cron-with-a-scoped-PAT path documented for automation.
All tests patch smtplib - no network.

Labels: a shared /print/asset-label/<type>/<id> view any asset detail
page opens - card or plain style, QR or barcode, configurable encoding.
Per-type qr_target_* templates plus label_default_style/codetype/encodes
settings on the Printing page. Measuring-tool labels default to encoding
their inspection-operation code (derived from the location name, e.g.
0615), so every tool in an area shares the area code - verified by
decoding the rendered QR. Machine labels default to the machine number;
blank-serial handled gracefully.

808 tests pass; both features verified live.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/components/EmailReportButton.vue

@@ -0,0 +1,53 @@
+<template>
+  <button class="btn btn-secondary" :disabled="sending" @click="emailReport">
+    {{ sending ? 'Sending...' : 'Email report' }}
+  </button>
+</template>
+
+<script setup>
+import { ref } from 'vue'
+import { reportsApi } from '../api'
+import { useToast } from '../composables/toast'
+import { apiError } from '../utils/apiError'
+
+// On-demand report delivery. Emails the given rows as an HTML table to the
+// site's Alert Recipients (or an explicit `to`). Automatic/scheduled sending is
+// out of scope for this app; point an external cron at POST /api/reports/email
+// with an API token to automate.
+const props = defineProps({
+  subject: { type: String, required: true },
+  columns: { type: Array, required: true },
+  rows: { type: Array, required: true },
+  intro: { type: String, default: '' },
+  to: { type: String, default: '' },
+})
+
+const toast = useToast()
+const sending = ref(false)
+
+async function emailReport() {
+  sending.value = true
+  try {
+    const payload = {
+      subject: props.subject,
+      columns: props.columns,
+      rows: props.rows,
+      intro: props.intro,
+    }
+    if (props.to) payload.to = props.to
+    const response = await reportsApi.email(payload)
+    const result = response.data?.data || {}
+    if (result.sent) {
+      toast.success('Report emailed.')
+    } else if (result.error) {
+      toast.error(`Report email failed: ${result.error}`)
+    } else {
+      toast.info(response.data?.message || 'Email is not configured.')
+    }
+  } catch (event) {
+    toast.error(apiError(event, 'Failed to email report'))
+  } finally {
+    sending.value = false
+  }
+}
+</script>