Release 1.2.1

- Fixed the dictionary update card taking too long to reappear after
  cancelling a download (DownloadManager).
- Bump agp 9.3.0 -> 9.3.1; migrate the release build type from
  isMinifyEnabled/isShrinkResources/proguardFiles to
  optimization { enable = true } with keep rules moved to
  app/src/release/keepRules/proguard-rules.keep.

app/src/main/java/com/example/research/feature/download/DownloadManager.kt

@@ -24,6 +24,7 @@ class DownloadManager(
         mutableDownloadProgressState.asStateFlow()
     private val mutex = Mutex()
     private var downloadJob: Job? = null
+    private var cancelCleanupJob: Job? = null
 
     companion object {
         private const val TAG = "DownloadManager"
@@ -44,6 +45,7 @@ class DownloadManager(
     fun startDownload() {
         if (downloadState.value is DownloadState.Loading) return
         if (!downloadScope.isActive) return
+        cancelCleanupJob = null
         downloadJob = downloadScope.launch {
             mutex.withLock {
                 try {
@@ -94,7 +96,7 @@ class DownloadManager(
                 } catch (e: Exception) {
                     if (e is CancellationException) {
                         updateDownloadProgressState(DownloadState.Cancelled, 0f)
-                        downloadScope.launch {
+                        cancelCleanupJob = downloadScope.launch {
                             try {
                                 dictionaryRepository.deleteUnprocessedFiles()
                             } catch (cleanupException: Exception) {
@@ -124,6 +126,7 @@ class DownloadManager(
     fun startDownloadForSources(sourceUrls: List<String>) {
         if (downloadState.value is DownloadState.Loading) return
         if (!downloadScope.isActive) return
+        cancelCleanupJob = null
         downloadJob = downloadScope.launch {
             mutex.withLock {
                 try {
@@ -168,7 +171,7 @@ class DownloadManager(
                 } catch (e: Exception) {
                     if (e is CancellationException) {
                         updateDownloadProgressState(DownloadState.Cancelled, 0f)
-                        downloadScope.launch {
+                        cancelCleanupJob = downloadScope.launch {
                             try {
                                 dictionaryRepository.deleteUnprocessedFiles()
                             } catch (cleanupException: Exception) {
@@ -195,10 +198,12 @@ class DownloadManager(
         }
     }
     fun cancelDownload() {
-        downloadJob?.cancel()
+        val jobToCancel = downloadJob
+        jobToCancel?.cancel()
         updateDownloadProgressState(DownloadState.Cancelled, 0f)
         downloadScope.launch {
-            delay(TERMINAL_STATE_DURATION)
+            jobToCancel?.join()
+            cancelCleanupJob?.join()
             if (downloadState.value == DownloadState.Cancelled) {
                 updateDownloadProgressState(DownloadState.Idle, 0f)
             }