Ajout de l'application Presencia (gestion des présences multi-sociétés)

Application complète : API Node/Express + PostgreSQL, frontend HTML/JS
mono-page, et déploiement Docker sur ports non standards (8781/4790/6543).

- Cadres : calendrier mensuel, saisie de présence par demi-journée
  (présent/absent/congé/RTT), validation de fin de mois qui verrouille
  leurs propres saisies.
- Admin : gestion des sociétés et utilisateurs (rattachement société <->
  cadre), consultation de tous les plannings, validation d'une société
  entière une fois tous ses cadres validés, réouverture en cas de
  correction, export PDF et Excel par société/mois.

backend/src/routes/export.js

@@ -0,0 +1,81 @@
+const express = require('express');
+const db = require('../db');
+const { requireAuth, requireAdmin } = require('../middleware/auth');
+const { buildCompanyWorkbook } = require('../utils/excel');
+const { buildCompanyPdf } = require('../utils/pdf');
+
+const router = express.Router();
+router.use(requireAuth, requireAdmin);
+
+async function loadCompanyData(companyId, year, month) {
+  const { rows: companyRows } = await db.query('SELECT id, name FROM companies WHERE id = $1', [companyId]);
+  const company = companyRows[0];
+  if (!company) return null;
+
+  const { rows: cadreRows } = await db.query(
+    `SELECT id, full_name FROM users WHERE company_id = $1 AND role = 'cadre' AND active = true ORDER BY full_name`,
+    [companyId]
+  );
+
+  const start = `${year}-${String(month).padStart(2, '0')}-01`;
+  const cadres = [];
+  for (const c of cadreRows) {
+    const { rows: entries } = await db.query(
+      `SELECT entry_date, period, status FROM attendance_entries
+       WHERE user_id = $1 AND entry_date >= $2::date AND entry_date < ($2::date + INTERVAL '1 month')`,
+      [c.id, start]
+    );
+    const map = new Map();
+    for (const e of entries) {
+      map.set(`${e.entry_date.toISOString().slice(0, 10)}:${e.period}`, e.status);
+    }
+    cadres.push({ id: c.id, fullName: c.full_name, entries: map });
+  }
+
+  return { company, cadres };
+}
+
+router.get('/excel/:companyId', async (req, res) => {
+  const year = parseInt(req.query.year, 10);
+  const month = parseInt(req.query.month, 10);
+  if (!year || !month) return res.status(400).json({ error: 'year et month requis' });
+
+  const data = await loadCompanyData(req.params.companyId, year, month);
+  if (!data) return res.status(404).json({ error: 'Société introuvable' });
+
+  const workbook = await buildCompanyWorkbook({
+    companyName: data.company.name,
+    year,
+    month,
+    cadres: data.cadres,
+  });
+
+  const filename = `presences_${data.company.name.replace(/\s+/g, '_')}_${year}-${String(month).padStart(2, '0')}.xlsx`;
+  res.setHeader('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
+  res.setHeader('Content-Disposition', `attachment; filename="${filename}"`);
+  await workbook.xlsx.write(res);
+  res.end();
+});
+
+router.get('/pdf/:companyId', async (req, res) => {
+  const year = parseInt(req.query.year, 10);
+  const month = parseInt(req.query.month, 10);
+  if (!year || !month) return res.status(400).json({ error: 'year et month requis' });
+
+  const data = await loadCompanyData(req.params.companyId, year, month);
+  if (!data) return res.status(404).json({ error: 'Société introuvable' });
+
+  const filename = `presences_${data.company.name.replace(/\s+/g, '_')}_${year}-${String(month).padStart(2, '0')}.pdf`;
+  res.setHeader('Content-Type', 'application/pdf');
+  res.setHeader('Content-Disposition', `attachment; filename="${filename}"`);
+
+  const doc = buildCompanyPdf({
+    companyName: data.company.name,
+    year,
+    month,
+    cadres: data.cadres,
+  });
+  doc.pipe(res);
+});
+
+module.exports = router;