fix(production): fix multiple remote server errors from nginx logs

- Fix 413 Request Entity Too Large: bump client_max_body_size to 256M,
  PHP post_max_size/upload_max_filesize to 256M, fastcgi timeouts to 300s
- Fix missing v_smtp_active view: add IF NOT EXISTS to all CREATE VIEW
  statements in schema.sql for idempotent migrates
- Fix bars.svg 404: create animated SVG spinner in app/public/assets/img/
- Fix nginx rate limiting: increase admin zone from 60r/m (1 r/s) to
  300r/m (5 r/s) with burst=30 to handle ~11 concurrent HTMX fragment
  GETs on contenus.php page load
- Add deploy-nginx recipe to justfile for uploading nginx config to server
- Database readonly issue mitigated by existing --chown + deploy-server.sh
  permissions fix
- Add comprehensive PHP/JS debugging logs for settings checkboxes:
  per-field raw POST values in error_log, console.log on htmx:beforeSend,
  htmx:sendError, htmx:afterRequest, toast lifecycle
- Fix toast auto-remove script: use getElementById with unique ID instead
  of querySelector which could remove wrong toast on rapid clicks

app/templates/admin/footer.php

@@ -15,6 +15,15 @@
 <?php endif; ?>
 <script src="/assets/js/htmx.min.js"></script>
 <script>
+// Global HTMX debugging for settings checkboxes
+document.body.addEventListener('htmx:sendError', function (e) {
+    console.error('[htmx:sendError] target=', e.target.id, 'detail=', e.detail);
+});
+document.body.addEventListener('htmx:beforeSend', function (e) {
+    if (e.target.id && (e.target.id.includes('fieldset-') || e.target.name)) {
+        console.log('[htmx:beforeSend] name=' + e.target.name + ' checked=' + e.target.checked, 'formData keys:', Array.from(new FormData(e.target.closest('fieldset'))).map(function(kv){return kv[0]}));
+    }
+});
 document.body.addEventListener('htmx:afterSettle', function (e) {
     if (e.target && e.target.id === 'toast-region') {
         var warn = e.target.querySelector('.toast--warning');