Add per-company backup reports (printable page and CSV)

/report.html shows one company's backups over the last 7, 30 or 90
days, chosen in the page and kept in the URL so reports can be
bookmarked or linked. Reached from Reports in the top bar, or a
company's name in a job's detail.

- Summary (jobs, runs, success rate, warnings, failures, overdue now);
  per job: run counts, success rate (successful / finished runs), last
  result and last successful backup; a day-by-day strip; every warning
  and failure with its message
- Print / Save as PDF: a print stylesheet prints light whatever the
  screen theme, hides the controls, keeps rows and strips whole across
  pages, and keeps the coloured cells and badges
- Days before a job was first known show as "Not monitored yet"
  rather than as missed backups, so a 90-day report for a newly added
  client doesn't look like 60 days of failures
- CSV of every run (full messages, times in the browser's time zone,
  UTF-8 BOM for Excel, formula-like values defused with a leading ')

Backend: GET /api/v1/tenants, /api/v1/reports/tenant and
/api/v1/reports/tenant.csv; periods capped at retention. tzdata added
for systems without time zone data. Frontend status and day-strip
helpers moved out of app.js into status.js / history.js for reuse.

Tested: 9 new backend tests; in the browser against the API with 30
days of demo history (summary, issues, strips, 7/30/90 switching,
CSV download with BOM, print styles applied on screen), mock mode and
phone width.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

public/js/app.js

@@ -2,6 +2,10 @@ import { CONFIG } from './config.js';
 import { getApi } from './api.js';
 import { el } from './dom.js';
 import { showSignedInUser } from './signed-in.js';
+import { STATUS, normalizeStatus, statusBadge } from './status.js';
+import {
+  localDayKey, dayLabelFmt, dayTickFmt, normalizeRun, buildDays, describeCounts,
+} from './history.js';
 import {
   parseDate, formatDateTime, formatTime, formatRelative, formatDuration, formatBytes,
 } from './format.js';
@@ -9,20 +13,6 @@ import {
 const api = await getApi();
 
 // ---------- Domain ----------
-// rank drives default sort: worst first
-const STATUS = {
-  failed:  { label: 'Failed',  icon: '✕', rank: 0 },
-  warning: { label: 'Warning', icon: '!', rank: 1 },
-  unknown: { label: 'Unknown', icon: '?', rank: 2 },
-  running: { label: 'Running', icon: '↻', rank: 3 },
-  success: { label: 'Success', icon: '✓', rank: 4 },
-};
-
-// Anything the backend sends that we don't recognise becomes "unknown" rather than breaking the UI
-function normalizeStatus(raw) {
-  const s = String(raw ?? '').toLowerCase();
-  return Object.hasOwn(STATUS, s) ? s : 'unknown';
-}
 
 function normalizeJob(j) {
   return {
@@ -62,6 +52,7 @@ const dom = {
   signedInEmail: $('#signed-in-email'),
   signOut: $('#sign-out'),
   adminLink: $('#admin-link'),
+  reportsLink: $('#reports-link'),
   lastUpdated: $('#last-updated'),
   errorBanner: $('#error-banner'),
   dialog: $('#detail-dialog'),
@@ -71,20 +62,6 @@ const dom = {
 };
 
 // ---------- Rendering ----------
-function statusBadge(status, { asButton = false, opensDialog = false, dataset = null, title = null } = {}) {
-  const { label, icon } = STATUS[status];
-  const content = [el('span', { class: 'badge__icon', 'aria-hidden': 'true' }, icon), label];
-  return asButton
-    ? el('button', {
-        type: 'button',
-        class: `badge badge--${status}`,
-        'aria-haspopup': opensDialog ? 'dialog' : null,
-        'aria-label': `${label} – view details`,
-        title,
-        dataset,
-      }, content)
-    : el('span', { class: `badge badge--${status}`, title }, content);
-}
 
 const runningTitle = (since) => (since ? `Running since ${formatDateTime(since)}` : null);
 
@@ -231,51 +208,6 @@ const modal = {
   runMessageError: null,
 };
 
-// Colour of a day cell: the worst thing that happened that day
-const DAY_SEVERITY = ['failed', 'warning', 'unknown', 'running', 'success'];
-
-const pad2 = (n) => String(n).padStart(2, '0');
-const localDayKey = (d) => `${d.getFullYear()}-${pad2(d.getMonth() + 1)}-${pad2(d.getDate())}`;
-const dayLabelFmt = new Intl.DateTimeFormat(undefined, { weekday: 'short', month: 'short', day: 'numeric' });
-const dayTickFmt = new Intl.DateTimeFormat(undefined, { month: 'short', day: 'numeric' });
-
-function normalizeRun(r) {
-  return {
-    id: String(r.id),
-    status: normalizeStatus(r.status),
-    startedAt: parseDate(r.started_at),
-    finishedAt: parseDate(r.finished_at),
-    duration: r.duration_seconds,
-    size: r.size_bytes,
-  };
-}
-
-function buildDays(runs, count) {
-  const today = new Date();
-  today.setHours(0, 0, 0, 0);
-  const days = [];
-  for (let i = count - 1; i >= 0; i--) {
-    const date = new Date(today);
-    date.setDate(date.getDate() - i);
-    days.push({ key: localDayKey(date), date, counts: {}, total: 0 });
-  }
-  const byKey = new Map(days.map((d) => [d.key, d]));
-  for (const run of runs) {
-    const day = byKey.get(localDayKey(run.startedAt));
-    if (!day) continue;
-    day.counts[run.status] = (day.counts[run.status] ?? 0) + 1;
-    day.total++;
-  }
-  for (const day of days) day.status = day.total ? DAY_SEVERITY.find((s) => day.counts[s]) : 'none';
-  return days;
-}
-
-function describeCounts(counts) {
-  return DAY_SEVERITY.filter((s) => counts[s])
-    .map((s) => `${counts[s]} ${STATUS[s].label.toLowerCase()}`)
-    .join(', ');
-}
-
 function detailRow(label, value) {
   if (value == null || value === '') return [];
   return [el('dt', {}, label), el('dd', {}, value)];
@@ -288,7 +220,8 @@ function renderSummarySection() {
   const lastStatus = detail?.last_status ? normalizeStatus(detail.last_status) : null;
 
   dom.detailTitle.textContent = detail?.job_name ?? job.name;
-  dom.detailSubtitle.textContent = detail?.company_name ?? job.company;
+  const company = detail?.company_name ?? job.company;
+  dom.detailSubtitle.replaceChildren(el('a', { href: reportUrl(company), title: `Backup report for ${company}` }, company));
 
   return el('section', {},
     el('div', { class: 'detail-status' },
@@ -517,7 +450,15 @@ dom.search.addEventListener('input', () => {
 
 dom.refreshBtn.addEventListener('click', () => refresh().then(schedulePoll));
 
+// A company's report page (keeps ?mock=1)
+function reportUrl(company) {
+  const params = new URLSearchParams({ tenant: company, days: '30' });
+  if (CONFIG.useMock) params.set('mock', '1');
+  return `/report.html?${params}`;
+}
+
 // ---------- Boot ----------
+dom.reportsLink.href = `/report.html${CONFIG.useMock ? '?mock=1' : ''}`;
 api.getMe().then(
   (me) => showSignedInUser(me, dom),
   (err) => console.error(err),  // not worth a banner: the jobs request will surface real problems