refactor(main): expose cold-start preferences as an InitialLaunch flow

Read the theme, locale, empty-library seed and section expansion
once in the application and collect them as state, instead of
blocking the UI thread with synchronous reads before setContent.

app/src/main/java/com/example/research/ReSearchApplication.kt

@@ -3,7 +3,9 @@ package com.example.research
 import android.app.Application
 import com.example.research.common.progress.DictionaryProgressStateHolder
 import com.example.research.common.util.NotificationHelper
+import com.example.research.core.domain.model.AppTheme
 import com.example.research.data.local.preferences.PreferencesManager
+import com.example.research.data.local.preferences.SectionExpansionStates
 import com.example.research.data.repository.LocalDictionaryRepository
 import com.example.research.feature.download.DownloadManager
 import com.example.research.feature.download.repository.DictionaryRepository
@@ -12,10 +14,25 @@ import com.example.research.feature.import.DictionaryImportManager
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import okhttp3.OkHttpClient
 import okhttp3.Protocol
 
+/**
+ * Values a cold start needs before the first composed frame: the initial
+ * theme, locale, empty-library navigation seed, and settings expansion state.
+ */
+data class InitialLaunch(
+    val theme: AppTheme,
+    val language: String,
+    val seedNoDictionaries: Boolean,
+    val sectionExpansion: SectionExpansionStates,
+)
+
 class ReSearchApplication : Application() {
 
     lateinit var preferencesManager: PreferencesManager
@@ -43,6 +60,9 @@ class ReSearchApplication : Application() {
         private set
     private val applicationScope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
 
+    private val _initialLaunch = MutableStateFlow<InitialLaunch?>(null)
+    val initialLaunch: StateFlow<InitialLaunch?> = _initialLaunch.asStateFlow()
+
     override fun onCreate() {
         super.onCreate()
 
@@ -53,6 +73,9 @@ class ReSearchApplication : Application() {
         applicationScope.launch(Dispatchers.IO) {
             preferencesManager.sanitizeDictionarySources()
         }
+        applicationScope.launch(Dispatchers.IO) {
+            _initialLaunch.value = loadInitialLaunch()
+        }
         localDictionaryRepository = LocalDictionaryRepository(this, preferencesManager = preferencesManager)
 
         okHttpClient = OkHttpClient.Builder()
@@ -121,6 +144,23 @@ class ReSearchApplication : Application() {
         downloadManager.onTerminal = dictionaryPipelineCoordinator::onDownloadTerminal
     }
 
+    private suspend fun loadInitialLaunch(): InitialLaunch {
+        val defaultExpansions = SectionExpansionStates(
+            isThemeExpanded = false,
+            isLanguageExpanded = false,
+            isDictionariesExpanded = true,
+        )
+        return InitialLaunch(
+            theme = runCatching { AppTheme.valueOf(preferencesManager.themeMode.first()) }
+                .getOrDefault(AppTheme.SYSTEM),
+            language = runCatching { preferencesManager.language.first() }.getOrDefault("system"),
+            seedNoDictionaries = runCatching { preferencesManager.hadNoDictionaries.first() }
+                .getOrDefault(true),
+            sectionExpansion = runCatching { preferencesManager.sectionExpansionStates() }
+                .getOrDefault(defaultExpansions),
+        )
+    }
+
     override fun onTrimMemory(level: Int) {
         super.onTrimMemory(level)
         if (::localDictionaryRepository.isInitialized) {