feat: complete Knowledge Base category management and fix structure

- Added full CRUD UI for categories (create/edit/delete)
- Category form with name, slug, description, display order, active toggle
- Categories displayed as editable tags with delete icons
- Removed duplicate second implementation entirely
- Fixed file structure to have single component
- Updated package.json with solid-markdown dependency
- Integrated Markdown component into article detail page for proper rendering

src/routes/admin/kb.tsx

@@ -460,6 +460,59 @@ export default function KnowledgeBasePage() {
             <Plus size={16} /> New Article
           </button>
         </div>
+       </div>
+
+      {/* Category Management */}
+      <div class="px-6 py-4 bg-white border-b border-gray-200">
+        <div class="flex justify-between items-center mb-3">
+          <h3 class="font-bold text-gray-800">Categories</h3>
+          <button onClick={openCreateCategory} class="px-3 py-1 text-xs font-bold text-white bg-[#FF5E13] rounded">Add Category</button>
+        </div>
+        <Show when={catMode() === 'create' || catMode() === 'edit'}>
+          <div class="mb-4 p-4 border border-gray-200 rounded-lg bg-gray-50">
+            <h4 class="font-bold text-gray-700 mb-2">{catMode() === 'edit' ? 'Edit Category' : 'Create New Category'}</h4>
+            <div class="grid grid-cols-2 gap-4 mb-3">
+              <div>
+                <label class="block text-xs font-bold text-gray-500 mb-1">Name</label>
+                <input type="text" value={catName()} onInput={(e) => setCatName(e.currentTarget.value)} class="w-full px-3 py-2 border border-gray-300 rounded focus:ring-2 focus:ring-[#FF5E13] outline-none" placeholder="Category Name" />
+              </div>
+              <div>
+                <label class="block text-xs font-bold text-gray-500 mb-1">Slug (optional)</label>
+                <input type="text" value={catSlug()} onInput={(e) => setCatSlug(e.currentTarget.value)} class="w-full px-3 py-2 border border-gray-300 rounded focus:ring-2 focus:ring-[#FF5E13] outline-none" placeholder="url-friendly-slug" />
+              </div>
+            </div>
+            <div class="mb-3">
+              <label class="block text-xs font-bold text-gray-500 mb-1">Description</label>
+              <input type="text" value={catDescription()} onInput={(e) => setCatDescription(e.currentTarget.value)} class="w-full px-3 py-2 border border-gray-300 rounded focus:ring-2 focus:ring-[#FF5E13] outline-none" placeholder="Brief description" />
+            </div>
+            <div class="flex items-center gap-4 mb-3">
+              <label class="flex items-center gap-2">
+                <span class="text-sm text-gray-600">Display Order:</span>
+                <input type="number" value={catDisplayOrder()} onInput={(e) => setCatDisplayOrder(parseInt(e.currentTarget.value) || 0)} class="w-20 px-3 py-2 border border-gray-300 rounded focus:ring-2 focus:ring-[#FF5E13] outline-none" />
+              </label>
+              <label class="flex items-center gap-2">
+                <input type="checkbox" checked={catIsActive()} onChange={(e) => setCatIsActive(e.target.checked)} />
+                <span class="text-sm text-gray-600">Active</span>
+              </label>
+            </div>
+            <Show when={catError()}>
+              <p class="text-sm text-red-600 mb-2">{catError()}</p>
+            </Show>
+            <div class="flex gap-2">
+              <button onClick={handleCancelCategory} class="px-4 py-2 text-sm font-bold text-gray-600 hover:text-gray-800">Cancel</button>
+              <button onClick={handleSaveCategory} disabled={catSaving()} class="px-4 py-2 text-sm font-bold text-white bg-[#0F172A] hover:bg-[#1E293B] rounded disabled:opacity-50">{catSaving() ? 'Saving...' : 'Save Category'}</button>
+            </div>
+          </div>
+        </Show>
+        <div class="flex flex-wrap gap-2">
+          <For each={categories()}>{cat => (
+            <div class="flex items-center gap-1 px-3 py-1.5 bg-gray-100 rounded-full text-sm">
+              <span>{cat.name}</span>
+              <button onClick={() => openEditCategory(cat)} class="text-gray-500 hover:text-[#FF5E13]"><Edit2 size={12}/></button>
+              <button onClick={() => handleDeleteCategory(cat.id)} class="text-gray-500 hover:text-red-500"><Trash2 size={12}/></button>
+            </div>
+          )}</For>
+        </div>
       </div>
 
       <Show when={view() === 'list'} fallback={