feat: add Settings page with hijri seasons CRUD

- Server: seasons CRUD routes + generic NocoDB helpers
- Client: Settings page at /settings with inline add/edit/delete
- Seasons stored in NocoDB Seasons table
- Vite proxy: /api/seasons routed to Express server
- Nav links added (desktop + mobile)
- Locale keys for EN + AR
- Seasons loaded non-blocking on app mount

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/App.css

@@ -851,6 +851,102 @@ table tbody tr:hover {
   accent-color: var(--accent);
 }
 
+/* Settings page */
+.settings-page {
+  padding: 24px;
+  max-width: 900px;
+}
+
+.settings-hint {
+  color: var(--text-secondary);
+  font-size: 0.875rem;
+  margin-bottom: 16px;
+}
+
+.season-chip {
+  display: inline-block;
+  padding: 4px 10px;
+  border-radius: 6px;
+  font-size: 0.8125rem;
+  font-weight: 600;
+  border: 1px solid;
+}
+
+.season-edit-name {
+  display: flex;
+  gap: 6px;
+  align-items: center;
+}
+
+.season-edit-name input[type="text"] {
+  flex: 1;
+  min-width: 80px;
+}
+
+.season-edit-name input[type="color"] {
+  width: 32px;
+  height: 32px;
+  padding: 2px;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  cursor: pointer;
+}
+
+.season-actions {
+  display: flex;
+  gap: 6px;
+}
+
+.btn-small {
+  padding: 4px 10px;
+  font-size: 0.75rem;
+  border-radius: 6px;
+  border: 1px solid var(--border);
+  background: var(--surface);
+  color: var(--text-primary);
+  cursor: pointer;
+}
+
+.btn-small:hover {
+  background: var(--hover);
+}
+
+.btn-small.btn-primary {
+  background: var(--accent);
+  color: white;
+  border-color: var(--accent);
+}
+
+.btn-small.btn-danger {
+  color: var(--danger, #dc2626);
+  border-color: var(--danger, #dc2626);
+}
+
+.btn-small.btn-danger:hover {
+  background: var(--danger, #dc2626);
+  color: white;
+}
+
+tr.add-row td {
+  border-top: 2px dashed var(--border);
+  padding-top: 12px;
+}
+
+tr.editing td {
+  background: var(--hover);
+}
+
+.settings-page input[type="text"],
+.settings-page input[type="number"],
+.settings-page input[type="date"] {
+  padding: 8px 10px;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  font-size: 0.8125rem;
+  background: var(--surface);
+  color: var(--text-primary);
+}
+
 .period-display {
   background: var(--bg);
   padding: 16px;