fix: release Lucene lock before retry on corrupt index (#8)

When initLucene() fails during the CheckIndex step, the IndexWriter
already holds the write.lock. The catch block deleted index files but
never closed the writer, so the retry attempt hit
LockObtainFailedException from the same JVM.

Author: fmaass

docs-core/src/main/java/com/sismics/docs/core/util/indexing/LuceneIndexingHandler.java

@@ -105,6 +105,17 @@ public void startUp() throws Exception {
         } catch (Exception e) {
             // An error occurred initializing Lucene, the index is out of date or broken, delete everything
             log.info("Unable to initialize Lucene, cleaning up the index: " + e.getMessage());
+
+            // Release the lock before deleting — initLucene may have partially succeeded
+            if (indexWriter != null) {
+                try { indexWriter.close(); } catch (Exception ignored) {}
+                indexWriter = null;
+            }
+            if (directory != null) {
+                try { directory.close(); } catch (Exception ignored) {}
+                directory = null;
+            }
+
             Path luceneDirectory = DirectoryUtil.getLuceneDirectory();
             Files.walk(luceneDirectory)
                     .sorted(Comparator.reverseOrder())