feat: implement background ebook indexing with progress tracking and real-time UI updates

src/NexusReader.Web/Program.cs

@@ -194,6 +194,7 @@ using (var scope = app.Services.CreateScope())
 
             await dbContext.Database.MigrateAsync();
             await DbInitializer.SeedAsync(services);
+            await TriggerBackgroundProcessingForUnindexedBooksAsync(services);
 
             if (logger.IsEnabled(LogLevel.Information))
             {
@@ -337,13 +338,16 @@ app.MapPost("/api/library/ingest", async ([FromBody] IngestEbookRequest request,
         ? Convert.FromBase64String(request.CoverImageBase64) 
         : null;
 
+    var tenantId = user.FindFirst("TenantId")?.Value ?? "global";
+
     var command = new IngestEbookCommand(
         request.Title,
         request.AuthorName,
         coverData,
         epubData,
         request.Description,
-        userId
+        userId,
+        tenantId
     );
 
     var result = await mediator.Send(command);
@@ -563,6 +567,50 @@ app.MapRazorComponents<App>()
 
 app.Run();
 
+async Task TriggerBackgroundProcessingForUnindexedBooksAsync(IServiceProvider services)
+{
+    var logger = services.GetRequiredService<ILogger<Program>>();
+    try
+    {
+        var dbContextFactory = services.GetRequiredService<IDbContextFactory<NexusReader.Data.Persistence.AppDbContext>>();
+        using var dbContext = await dbContextFactory.CreateDbContextAsync();
+        
+        var unindexedEbooks = await dbContext.Ebooks
+            .Where(e => !e.IsReadyForReading)
+            .ToListAsync();
+            
+        if (unindexedEbooks.Any())
+        {
+            logger.LogInformation("[Startup] Found {Count} un-indexed ebooks. Triggering background processing...", unindexedEbooks.Count);
+            
+            foreach (var ebook in unindexedEbooks)
+            {
+                logger.LogInformation("[Startup] Queuing background processing for ebook: '{Title}' ({Id})", ebook.Title, ebook.Id);
+                
+                _ = Task.Run(async () =>
+                {
+                    try
+                    {
+                        using var scope = services.CreateScope();
+                        var scopedMediator = scope.ServiceProvider.GetRequiredService<IMediator>();
+                        await scopedMediator.Send(new ProcessEbookCommand(ebook.Id, ebook.UserId, ebook.TenantId));
+                    }
+                    catch (Exception ex)
+                    {
+                        using var scope = services.CreateScope();
+                        var scopedLogger = scope.ServiceProvider.GetRequiredService<ILogger<Program>>();
+                        scopedLogger.LogError(ex, "Failed to run background processing for ebook {EbookId} on startup", ebook.Id);
+                    }
+                });
+            }
+        }
+    }
+    catch (Exception ex)
+    {
+        logger.LogError(ex, "Error checking or triggering background processing for unindexed books on startup.");
+    }
+}
+
 public record KnowledgeRequest(string Text, Guid? EbookId = null);
 public record GroundednessRequest(string Answer, string Context);
 public record SemanticSearchRequest(string QueryText, int Limit = 5);