feat(intelligence): implement global hybrid search engine and monetization logic

- Created IUserLibraryStore and IVectorSearchStore abstractions to decouple relational DB and Qdrant gRPC logic from Application Layer
- Implemented MediatR GetGlobalIntelligenceQuery with value-first teaser RAG monetization logic
- Registered new request and response DTOs in AppJsonContext for Native AOT source-generated serialization
- Bound RagMonetizationOptions via IOptions pattern in appsettings.json configuration
- Added POST /api/intelligence endpoint on server and implemented GetGlobalIntelligenceAsync in WASM client service
- Refactored Intelligence.razor to consume the backend-driven global hybrid search Q&A engine

src/NexusReader.Infrastructure/DependencyInjection.cs

@@ -2,6 +2,7 @@ using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Configuration;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.AI;
+using NexusReader.Application.Common;
 using GeminiDotnet;
 using GeminiDotnet.Extensions.AI;
 using NexusReader.Data.Persistence;
@@ -76,6 +77,7 @@ public static class DependencyInjection
 
         services.Configure<AiSettings>(configuration.GetSection(AiSettings.SectionName));
         services.Configure<StripeSettings>(configuration.GetSection(StripeSettings.SectionName));
+        services.Configure<RagMonetizationOptions>(configuration.GetSection(RagMonetizationOptions.SectionName));
         var aiSettings = configuration.GetSection(AiSettings.SectionName).Get<AiSettings>() ?? new AiSettings();
 
         if (string.IsNullOrWhiteSpace(aiSettings.ApiKey) || aiSettings.ApiKey == "PLACEHOLDER")
@@ -127,6 +129,8 @@ public static class DependencyInjection
         services.AddScoped<IEbookRepository, EbookRepository>();
         services.AddScoped<IQuizResultRepository, QuizResultRepository>();
         services.AddScoped<IConceptsMapReadRepository, ConceptsMapReadRepository>();
+        services.AddScoped<IUserLibraryStore, UserLibraryStore>();
+        services.AddScoped<IVectorSearchStore, VectorSearchStore>();
 
         // Fix #2: SignalR broadcaster (scoped, wraps IHubContext which is itself a singleton wrapper)
         services.AddScoped<ISyncBroadcaster, SignalRSyncBroadcaster>();