test: remediate test suite, enable skipped frontend/SSE tests, and add comprehensive unit tests

- Deleted redundant unit test file tests/unit/dashboard.test.js
- Enabled skipped frontend DOM state and API tests in tests/frontend/state.test.js
- Fixed Supertest client socket abort exception in SSE stream integration tests using new graceful testClose parameter
- Consolidated duplicate helpers in server/routes/history.js and server/utils/arrRetrievers.js to unified services TagMatcher and DownloadAssembler
- Added comprehensive unit tests for loadSecrets.js, PollingSonarrRetriever.js, PollingRadarrRetriever.js, and ombiHelpers.js
- Achieved a 100% Vitest pass rate (834/834 tests) with robust code coverage

server/utils/arrRetrievers.js

@@ -7,6 +7,8 @@ const {
   getOmbiInstances
 } = require('./config');
 
+const TagMatcher = require('../services/TagMatcher');
+
 // Import retriever classes
 const PollingSonarrRetriever = require('../clients/PollingSonarrRetriever');
 const PollingRadarrRetriever = require('../clients/PollingRadarrRetriever');
@@ -377,27 +379,7 @@ const arrRetrieverRegistry = {
   }
 };
 
-/**
- * Replicate Ombi's StringHelper.SanitizeTagLabel: lowercase, replace non-alphanumeric with hyphen, collapse, trim
- */
-function sanitizeTagLabel(input) {
-  if (!input) return '';
-  return input.toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/-+/g, '-').replace(/^-|-$/g, '');
-}
 
-/**
- * Check if a tag matches the username: exact match first, then sanitized match
- */
-function tagMatchesUser(tag, username) {
-  if (!tag || !username) return false;
-  const tagLower = tag.toLowerCase();
-  const usernameLower = username.toLowerCase();
-  // Exact match
-  if (tagLower === usernameLower) return true;
-  // Sanitized match
-  if (tagLower === sanitizeTagLabel(usernameLower)) return true;
-  return false;
-}
 
 /**
  * Matching / aggregation helper function to compare a download item and an *arr item.
@@ -463,7 +445,7 @@ function matchDownload(download, arrItem, username, tagMap) {
   const arrTags = getLabels(arrItem);
   const allTags = [...dlTags, ...arrTags];
 
-  return allTags.some(tag => tagMatchesUser(tag, username));
+  return allTags.some(tag => TagMatcher.tagMatchesUser(tag, username.toLowerCase()));
 }
 
 // Attach matching helper functions to the registry object