refactor: remove patch_detector and use gameVersion field in match_collector

frontend/server/utils/mongo.ts

@@ -19,11 +19,38 @@ async function connectToDatabase() {
   return client
 }
 
-async function fetchLatestPatch(client: MongoClient) {
-  const database = client.db('patches')
-  const patches = database.collection('patches')
-  const latestPatch = await patches.find().limit(1).sort({ date: -1 }).next()
-  return latestPatch!.patch as string
+/**
+ * Get the latest patch from existing match collections in the database.
+ * Collections are named like "15.1_EUW1", "15.2_NA1", etc.
+ */
+async function fetchLatestPatch(client: MongoClient): Promise<string> {
+  const matchesDb = client.db('matches')
+  const collections = await matchesDb.listCollections().toArray()
+  const collectionNames = collections.map(c => c.name)
+
+  // Extract unique patch versions from collection names
+  const patches = new Set<string>()
+  for (const name of collectionNames) {
+    // Collection names are either "patch_platform" or just "patch"
+    const patch = name.split('_')[0]
+    if (patch && /^\d+\.\d+$/.test(patch)) {
+      patches.add(patch)
+    }
+  }
+
+  if (patches.size === 0) {
+    throw new Error('No patch collections found in database')
+  }
+
+  // Sort patches and return the latest (highest version number)
+  const sortedPatches = Array.from(patches).sort((a, b) => {
+    const [aMajor, aMinor] = a.split('.').map(Number)
+    const [bMajor, bMinor] = b.split('.').map(Number)
+    if (aMajor !== bMajor) return bMajor - aMajor
+    return bMinor - aMinor
+  })
+
+  return sortedPatches[0]
 }
 
 /**