Add removal/blacklist tools, Arabic UI, and a persistent sign-in error

Authorisation: driver/deleteCaptain.php permanently deletes a captain and had
no role check at all — any valid token, including a driver's or passenger's,
could delete captains. It now requires super_admin. The two unblacklist
endpoints had no role check either and now require an admin role.

Console:
- Blacklist & removal screen (super admin only): current blocks, permanent
  removal, and lifting a block. Deletion additionally requires the phone
  number to be retyped, because the row is deleted outright.
- Arabic interface with full RTL layout and a language toggle. Sidebar,
  content offset, input affordances, toasts and directional icons all mirror;
  numbers, identifiers and the diagnostics output stay LTR.
- Sign-in failures now render in the form and stay there. They were only
  shown as a toast, which disappears before it can be read — a locked
  account or a rejected device looked like the page simply returning to
  the login screen with no explanation.

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

dashboard/siro-admin/css/main.css

@@ -1384,3 +1384,127 @@ textarea.form-input { text-align: start; }
 }
 
 .card-header { gap: 1rem; flex-wrap: wrap; }
+
+/* Destructive action button */
+.btn-danger {
+  background: var(--danger-bg);
+  border-color: rgba(244, 63, 94, 0.45);
+  color: var(--danger);
+  font-weight: 600;
+}
+
+.btn-danger:hover { background: rgba(244, 63, 94, 0.28); }
+
+/* ==========================================================================
+   Right-to-left layout (Arabic)
+   The base layout is written LTR with physical properties, so RTL flips the
+   fixed sidebar, the content offset and anything anchored to a screen edge.
+   ========================================================================== */
+.lang-toggle {
+  font-weight: 700;
+  font-size: 0.85rem;
+  font-family: 'Outfit', sans-serif;
+}
+
+[dir="rtl"] .sidebar {
+  left: auto;
+  right: 0;
+  border-right: none;
+  border-left: 1px solid var(--border-color);
+}
+
+[dir="rtl"] .main-wrapper {
+  margin-left: 0;
+  margin-right: var(--sidebar-width);
+}
+
+[dir="rtl"] .nav-item.active::before,
+[dir="rtl"] .nav-item::before {
+  left: auto;
+  right: 0;
+}
+
+[dir="rtl"] .toast {
+  right: auto;
+  left: 24px;
+}
+
+/* The icon sits at the inline start; in RTL that is the right edge, and the
+   input's reserved padding must move with it. */
+[dir="rtl"] .form-input-group i {
+  left: auto;
+  right: 1rem;
+}
+
+[dir="rtl"] .form-input-group .form-input {
+  padding-left: 1rem;
+  padding-right: 2.8rem;
+}
+
+[dir="rtl"] .search-box i {
+  left: auto;
+  right: 0.9rem;
+}
+
+[dir="rtl"] .search-box input {
+  padding-left: 1rem;
+  padding-right: 2.5rem;
+}
+
+[dir="rtl"] .nav-count { margin-left: 0; margin-right: auto; }
+[dir="rtl"] .card-sub { margin-left: 0; margin-right: 0.4rem; }
+[dir="rtl"] .kv-row strong { text-align: left; }
+[dir="rtl"] .stop-list { padding-left: 0; padding-right: 1.2rem; }
+
+/* Directional icons must mirror, plain symbols must not */
+[dir="rtl"] .route-cell .ph-arrow-right,
+[dir="rtl"] .btn .ph-caret-left,
+[dir="rtl"] .btn .ph-caret-right {
+  transform: scaleX(-1);
+}
+
+/* Numbers, code and diagnostics stay LTR even inside an RTL page */
+[dir="rtl"] .diagnostics,
+[dir="rtl"] .device-note code,
+[dir="rtl"] .stat-value,
+[dir="rtl"] .kpi-tile-value {
+  direction: ltr;
+  text-align: start;
+}
+
+@media (max-width: 992px) {
+  [dir="rtl"] .sidebar { transform: translateX(100%); }
+  [dir="rtl"] .sidebar.open { transform: translateX(0); }
+  [dir="rtl"] .main-wrapper { margin-right: 0; }
+}
+
+/* Persistent sign-in error */
+.login-error {
+  display: flex;
+  align-items: flex-start;
+  gap: 0.6rem;
+  margin-top: 1.25rem;
+  padding: 0.8rem 0.95rem;
+  border-radius: var(--radius-md);
+  background: var(--danger-bg);
+  border: 1px solid rgba(244, 63, 94, 0.4);
+  color: var(--danger);
+  font-size: 0.82rem;
+  line-height: 1.55;
+}
+
+/* display:flex would otherwise override the [hidden] attribute */
+.login-error[hidden] { display: none; }
+
+.login-error i { font-size: 1.1rem; flex-shrink: 0; }
+.login-error div { display: flex; flex-direction: column; gap: 0.25rem; min-width: 0; }
+.login-error strong { color: var(--text-main); font-weight: 600; }
+
+.login-error span {
+  color: var(--text-muted);
+  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
+  font-size: 0.72rem;
+  word-break: break-all;
+  direction: ltr;
+  text-align: start;
+}