Add Game Asset Preservation System Foundation

DATABASE SCHEMA:
+ GameAsset entity added to RR3DbContext
  - Asset identification (ID, type, filename)
  - EA CDN tracking (original URL, CDN path)
  - Local storage (path, size, SHA256)
  - Metadata (downloads, access count, timestamps)
  - Game-specific (carId, trackId, category)

FEATURES:
- Track all cached assets in database
- Store EA CDN URLs while available
- SHA256 integrity checking
- Access statistics
- Category organization
- Version tracking

PURPOSE:
Foundation for full asset caching system.
Next step: AssetsController with EA CDN proxying.

STORAGE STRUCTURE:
wwwroot/assets/
├── cars/
├── tracks/
├── textures/
├── audio/
├── models/
└── misc/

PRESERVATION STRATEGY:
Phase 1 (EA online): Proxy + cache assets
Phase 2 (EA offline): Serve from cache
Result: Complete game preservation! 🎮💾

Package added: Microsoft.Extensions.Http (for CDN proxying)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

RR3CommunityServer/obj/project.nuget.cache

@@ -1,6 +1,6 @@
 {
   "version": 2,
-  "dgSpecHash": "EgnTyLkcYZw=",
+  "dgSpecHash": "F/KzlzQBI38=",
   "success": true,
   "projectFilePath": "E:\\rr3\\RR3CommunityServer\\RR3CommunityServer\\RR3CommunityServer.csproj",
   "expectedPackageFiles": [
@@ -23,14 +23,20 @@
     "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.apidescription.server\\6.0.5\\microsoft.extensions.apidescription.server.6.0.5.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.caching.abstractions\\8.0.0\\microsoft.extensions.caching.abstractions.8.0.0.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.caching.memory\\8.0.1\\microsoft.extensions.caching.memory.8.0.1.nupkg.sha512",
-    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.configuration.abstractions\\8.0.0\\microsoft.extensions.configuration.abstractions.8.0.0.nupkg.sha512",
-    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.dependencyinjection\\8.0.1\\microsoft.extensions.dependencyinjection.8.0.1.nupkg.sha512",
-    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.dependencyinjection.abstractions\\8.0.2\\microsoft.extensions.dependencyinjection.abstractions.8.0.2.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.configuration\\10.0.3\\microsoft.extensions.configuration.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.configuration.abstractions\\10.0.3\\microsoft.extensions.configuration.abstractions.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.configuration.binder\\10.0.3\\microsoft.extensions.configuration.binder.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.dependencyinjection\\10.0.3\\microsoft.extensions.dependencyinjection.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.dependencyinjection.abstractions\\10.0.3\\microsoft.extensions.dependencyinjection.abstractions.10.0.3.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.dependencymodel\\8.0.2\\microsoft.extensions.dependencymodel.8.0.2.nupkg.sha512",
-    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.logging\\8.0.1\\microsoft.extensions.logging.8.0.1.nupkg.sha512",
-    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.logging.abstractions\\8.0.2\\microsoft.extensions.logging.abstractions.8.0.2.nupkg.sha512",
-    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.options\\8.0.2\\microsoft.extensions.options.8.0.2.nupkg.sha512",
-    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.primitives\\8.0.0\\microsoft.extensions.primitives.8.0.0.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.diagnostics\\10.0.3\\microsoft.extensions.diagnostics.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.diagnostics.abstractions\\10.0.3\\microsoft.extensions.diagnostics.abstractions.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.http\\10.0.3\\microsoft.extensions.http.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.logging\\10.0.3\\microsoft.extensions.logging.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.logging.abstractions\\10.0.3\\microsoft.extensions.logging.abstractions.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.options\\10.0.3\\microsoft.extensions.options.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.options.configurationextensions\\10.0.3\\microsoft.extensions.options.configurationextensions.10.0.3.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\microsoft.extensions.primitives\\10.0.3\\microsoft.extensions.primitives.10.0.3.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\microsoft.openapi\\1.6.14\\microsoft.openapi.1.6.14.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\mono.texttemplating\\2.2.1\\mono.texttemplating.2.2.1.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\sqlitepclraw.bundle_e_sqlite3\\2.1.6\\sqlitepclraw.bundle_e_sqlite3.2.1.6.nupkg.sha512",
@@ -49,6 +55,7 @@
     "C:\\Users\\admin\\.nuget\\packages\\system.composition.hosting\\6.0.0\\system.composition.hosting.6.0.0.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\system.composition.runtime\\6.0.0\\system.composition.runtime.6.0.0.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\system.composition.typedparts\\6.0.0\\system.composition.typedparts.6.0.0.nupkg.sha512",
+    "C:\\Users\\admin\\.nuget\\packages\\system.diagnostics.diagnosticsource\\10.0.3\\system.diagnostics.diagnosticsource.10.0.3.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\system.io.pipelines\\6.0.3\\system.io.pipelines.6.0.3.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\system.memory\\4.5.3\\system.memory.4.5.3.nupkg.sha512",
     "C:\\Users\\admin\\.nuget\\packages\\system.reflection.metadata\\6.0.1\\system.reflection.metadata.6.0.1.nupkg.sha512",