Channels UI + read/unread + unique views + style polish

shine-server-db/src/main/java/shine/db/DatabaseInitializer.java

@@ -346,6 +346,34 @@ public final class DatabaseInitializer {
                 ON message_stats (to_login);
                 """);
 
+            // 8.0) message_views_state (уникальный просмотр/прочтение сообщения пользователем)
+            st.executeUpdate("""
+                CREATE TABLE IF NOT EXISTS message_views_state (
+                    viewer_login      TEXT    NOT NULL,
+                    to_bch_name       TEXT    NOT NULL,
+                    to_block_number   INTEGER NOT NULL,
+                    to_block_hash     BLOB    NOT NULL,
+                    first_seen_at_ms  INTEGER NOT NULL,
+
+                    UNIQUE (
+                        viewer_login,
+                        to_bch_name,
+                        to_block_number,
+                        to_block_hash
+                    )
+                );
+                """);
+
+            st.executeUpdate("""
+                CREATE INDEX IF NOT EXISTS idx_message_views_state_target
+                ON message_views_state (to_bch_name, to_block_number, to_block_hash);
+                """);
+
+            st.executeUpdate("""
+                CREATE INDEX IF NOT EXISTS idx_message_views_state_viewer_channel
+                ON message_views_state (viewer_login, to_bch_name);
+                """);
+
             // 8.1) reactions_state (идемпотентный LIKE/UNLIKE per actor/target)
             st.executeUpdate("""
                 CREATE TABLE IF NOT EXISTS reactions_state (