feat: Add INCLUDE_CATEGORY_IDS environment variable and logic to promote specified categories to root level.

.env.example

@@ -13,4 +13,5 @@ JTL_STEUERZONE_ID=1
 SERVER_PORT=3991
 SERVER_HOST=127.0.0.1
 SYNC_INTERVAL_MS=600000
-EXCLUDE_CATEGORY_IDS=
+EXCLUDE_CATEGORY_IDS=
+INCLUDE_CATEGORY_IDS=

src/utils/category-tree-utils.js

@@ -15,6 +15,19 @@ export function parseExcludedIds() {
     );
 }
 
+/**
+ * Parse included category IDs from environment variable
+ * @returns {Set<number>} - Set of included category IDs
+ */
+export function parseIncludedIds() {
+    return new Set(
+        (process.env.INCLUDE_CATEGORY_IDS || '')
+            .split(',')
+            .map(id => parseInt(id.trim()))
+            .filter(id => !isNaN(id))
+    );
+}
+
 /**
  * Build a hierarchical category tree from flat data
  * @param {Array} categories - Category records with kKategorie, kOberKategorie, nSort
@@ -51,6 +64,7 @@ export function buildTree(categories, names, articleCounts, images, applyRootFil
 
     const rootNodes = [];
     const excludedIds = parseExcludedIds();
+    const includedIds = parseIncludedIds();
 
     // Build hierarchy
     categories.forEach(cat => {
@@ -81,6 +95,23 @@ export function buildTree(categories, names, articleCounts, images, applyRootFil
         }
     }
 
+    // Add included categories to the result nodes (promoting them to root level)
+    includedIds.forEach(id => {
+        // Skip if excluded (exclusion takes precedence)
+        if (excludedIds.has(id)) return;
+
+        const node = categoryMap.get(id);
+        if (node) {
+            // Remove subcategories for included categories as requested
+            node.children = [];
+
+            // Avoid duplicates if the node is already in the result list
+            if (!resultNodes.includes(node)) {
+                resultNodes.push(node);
+            }
+        }
+    });
+
     // Sort children and remove nSort
     for (const node of categoryMap.values()) {
         node.children.sort((a, b) => a.nSort - b.nSort || a.kKategorie - b.kKategorie);