Enable WAL on the Reader database to prevent onStart ANRs (#23116)

Without WAL, Android caps the reader DB connection pool at one connection,
serializing all reads/writes across threads. A main-thread tag read in
ReaderPostListFragment.onStart could then block behind a background write
(purge/reset/addOrUpdatePosts) long enough to trigger an ANR.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: adalpari

WordPress/src/main/java/org/wordpress/android/datasets/ReaderDatabase.java

@@ -187,6 +187,17 @@ public ReaderDatabase(Context context) {
         super(context, DB_NAME, null, DB_VERSION);
     }
 
+    @Override
+    public void onConfigure(SQLiteDatabase db) {
+        super.onConfigure(db);
+        // Enable Write-Ahead Logging so reads and a single writer can run concurrently. Without WAL,
+        // Android caps the connection pool at a single connection for the whole reader DB, which
+        // serializes every read/write across all threads. That serialization causes ANRs when a
+        // main-thread read (e.g. reloading Reader tags in onStart) blocks behind a background write
+        // such as purge()/reset()/addOrUpdatePosts(). See ReaderTagTable.getTagFromEndpoint ANR.
+        db.enableWriteAheadLogging();
+    }
+
     @Override
     public void onCreate(SQLiteDatabase db) {
         createAllTables(db);