Fix minor code review issues: null check, redundant condition, grammar

Co-authored-by: PhenX <42170+PhenX@users.noreply.github.com>

Author: Copilot

src/PhenX.EntityFrameworkCore.BulkInsert/Graph/GraphBulkInsertOrchestrator.cs

@@ -383,8 +383,7 @@ private async Task InsertJoinEntities(
     {
         // Skip dictionary-based shared-type join entities as they are not supported
         // by the bulk insert infrastructure (requires typed IEnumerable<T>)
-        if (joinEntityType == typeof(Dictionary<string, object>) ||
-            typeof(IDictionary<string, object>).IsAssignableFrom(joinEntityType))
+        if (typeof(IDictionary<string, object>).IsAssignableFrom(joinEntityType))
         {
             _logger?.LogWarning(
                 "IncludeGraph: Skipping join table insertion for shared-type entity (Dictionary<string, object>). " +

src/PhenX.EntityFrameworkCore.BulkInsert/Graph/GraphEntityCollector.cs

@@ -156,7 +156,7 @@ private static void SetInverseNavigation(object parentEntity, object childEntity
         // Only set inverse navigations that are reference properties (not collections).
         // If the inverse is a collection, the parent should be added to the collection,
         // not assigned directly (which would cause an invalid cast).
-        if (navigation.Navigation is INavigation { Inverse.IsCollection: true })
+        if (navigation.Navigation is INavigation nav && nav.Inverse?.IsCollection == true)
         {
             // Skip: inverse is a collection, not a reference property
             return;

tests/PhenX.EntityFrameworkCore.BulkInsert.Tests/Tests/Graph/GraphTestsBase.cs

@@ -592,7 +592,7 @@ await _context.ExecuteBulkInsertAsync(blogs, options =>
     [SkippableFact]
     public async Task InsertGraph_LargeScale()
     {
-        // Arrange - Create blogs with children each (Posts, Tags, BlogSettings)
+        // Arrange - Create blogs, each with their children (Posts, Tags, BlogSettings)
         // This tests correctness with a reasonable amount of data that won't cause CI timeouts
         const int blogCount = 50;
         const int postsPerBlog = 10;