feat(logging): add logging to chat bloc history and attachments

apps/lib/features/chat/presentation/bloc/chat_bloc.dart

@@ -214,7 +214,16 @@ class ChatBloc extends Cubit<ChatState> implements ChatOrchestrator {
 
     final epoch = ++_sessionEpoch;
     _activeUserId = normalizedUserId;
+    try {
       await _service.setUserContext(normalizedUserId);
+    } catch (e, stackTrace) {
+      _logger.error(
+        message: 'Failed to set user context',
+        error: e,
+        stackTrace: stackTrace,
+        extra: {'user_id': normalizedUserId},
+      );
+    }
     if (epoch != _sessionEpoch) {
       return;
     }

apps/lib/features/chat/presentation/bloc/chat_bloc_attachments.dart

@@ -75,7 +75,13 @@ extension _ChatBlocAttachments on ChatBloc {
         final bytes = await _service.fetchAttachmentPreview(previewPath);
         _attachmentPreviewCache[previewPath] = bytes;
         return bytes;
-      } catch (_) {
+      } catch (e, stackTrace) {
+        _logger.error(
+          message: 'Failed to load attachment preview',
+          error: e,
+          stackTrace: stackTrace,
+          extra: {'preview_path': previewPath},
+        );
         return null;
       } finally {
         _attachmentPreviewInflight.remove(previewPath);

apps/lib/features/chat/presentation/bloc/chat_bloc_history.dart

@@ -22,6 +22,12 @@ extension _ChatBlocHistory on ChatBloc {
           hasEarlierHistory: snapshot.hasMore,
         ),
       );
+    } catch (e, stackTrace) {
+      _logger.error(
+        message: 'Failed to load chat history',
+        error: e,
+        stackTrace: stackTrace,
+      );
     } finally {
       if (epoch == _sessionEpoch) {
         emit(state.copyWith(isLoadingHistory: false));
@@ -53,6 +59,12 @@ extension _ChatBlocHistory on ChatBloc {
           hasEarlierHistory: snapshot.hasMore,
         ),
       );
+    } catch (e, stackTrace) {
+      _logger.error(
+        message: 'Failed to load more chat history',
+        error: e,
+        stackTrace: stackTrace,
+      );
     } finally {
       if (epoch == _sessionEpoch) {
         emit(state.copyWith(isLoadingHistory: false));