feat(cms): enhance content editors and implement automatic ID generation

Improve the CMS administration interface across multiple pages (Accreditation, Admissions, History, Partnerships, and Policies) with a focus on usability and data integrity.
Key changes include:
- Implement `ensureUniqueIds` utility to automatically generate and maintain unique slugs for content items, removing the need for manual ID entry in the UI.
- Refactor the Admissions calculator to support detailed per-option editing via a new dedicated view and routes.
- Replace basic datalists with a custom, searchable icon combobox component for better visual selection.
- Update `_renderSingletonPageView` to handle active tab persistence via query parameters.
- Streamline editor configurations by removing redundant fields and improving help text.
- Enhance the Admissions "Key Dates" editor with a dynamic table interface for managing columns and rows.
- Normalize data payloads in controllers to ensure consistent API responses and internal linking.

views/layouts/main.ejs

@@ -477,6 +477,150 @@
       margin-left: auto;
     }
 
+    .cms-icon-combobox {
+      position: relative;
+    }
+
+    .cms-icon-dropdown-trigger {
+      width: 100%;
+      display: flex;
+      align-items: center;
+      justify-content: space-between;
+      gap: 0.75rem;
+      border: 1px solid rgba(148, 163, 184, 0.18);
+      border-radius: 10px;
+      background: #fff;
+      padding: 0.75rem;
+      color: #334155;
+      text-align: left;
+    }
+
+    .cms-icon-dropdown-trigger:hover {
+      border-color: rgba(184, 183, 106, 0.55);
+      background: rgba(248, 250, 252, 0.96);
+    }
+
+    .cms-icon-combobox.is-open .cms-icon-dropdown-trigger {
+      border-color: rgba(184, 183, 106, 0.65);
+      box-shadow: 0 0 0 0.2rem rgba(184, 183, 106, 0.12);
+    }
+
+    .cms-icon-dropdown-value {
+      display: flex;
+      align-items: center;
+      gap: 0.75rem;
+      min-width: 0;
+      flex: 1;
+    }
+
+    .cms-icon-dropdown-text {
+      min-width: 0;
+      display: flex;
+      flex-direction: column;
+      gap: 0.1rem;
+    }
+
+    .cms-icon-dropdown-text strong,
+    .cms-icon-dropdown-text span {
+      display: block;
+      overflow: hidden;
+      text-overflow: ellipsis;
+      white-space: nowrap;
+    }
+
+    .cms-icon-dropdown-caret {
+      color: #94a3b8;
+      transition: transform 0.18s ease;
+    }
+
+    .cms-icon-combobox.is-open .cms-icon-dropdown-caret {
+      transform: rotate(180deg);
+    }
+
+    .cms-icon-preview {
+      width: 44px;
+      min-width: 44px;
+      height: 44px;
+      display: inline-flex;
+      align-items: center;
+      justify-content: center;
+      border: 1px solid rgba(148, 163, 184, 0.18);
+      border-radius: 8px;
+      background: #fff;
+      color: #334155;
+    }
+
+    .cms-icon-dropdown-panel {
+      position: absolute;
+      top: calc(100% + 0.5rem);
+      left: 0;
+      right: 0;
+      z-index: 30;
+      background: #fff;
+      border: 1px solid rgba(148, 163, 184, 0.18);
+      border-radius: 10px;
+      padding: 0.75rem;
+      box-shadow: 0 10px 30px rgba(15, 23, 42, 0.12);
+    }
+
+    .cms-icon-dropdown-panel .form-control {
+      margin-bottom: 0.75rem;
+    }
+
+    .cms-icon-options {
+      max-height: 220px;
+      overflow: auto;
+      display: flex;
+      flex-direction: column;
+      gap: 0.375rem;
+    }
+
+    .cms-icon-option {
+      display: flex;
+      align-items: center;
+      justify-content: space-between;
+      gap: 0.75rem;
+      width: 100%;
+      border: 1px solid rgba(148, 163, 184, 0.18);
+      background: #fff;
+      color: #334155;
+      border-radius: 8px;
+      padding: 0.55rem 0.7rem;
+      text-align: left;
+      font-size: 0.875rem;
+    }
+
+    .cms-icon-option-main {
+      min-width: 0;
+      display: flex;
+      align-items: center;
+      gap: 0.625rem;
+    }
+
+    .cms-icon-option-main span {
+      overflow: hidden;
+      text-overflow: ellipsis;
+      white-space: nowrap;
+    }
+
+    .cms-icon-option:hover {
+      border-color: rgba(184, 183, 106, 0.55);
+      background: rgba(248, 250, 252, 0.96);
+      color: #0f172a;
+    }
+
+    .cms-icon-option.is-active {
+      border-color: rgba(184, 183, 106, 0.65);
+      background: rgba(184, 183, 106, 0.12);
+      color: #0f172a;
+    }
+
+    .cms-icon-option-empty {
+      color: #94a3b8;
+      font-size: 0.75rem;
+      padding: 0.5rem 0.25rem 0;
+    }
+
     main {
       flex: 1;
       z-index: 1;