Properly handle @defer in DocumentRewriter

[tobias-tengler]

No description provided.

[Copilot]

Pull request overview

This PR extends Fusion’s DocumentRewriter to properly account for executable @defer directives during selection rewriting/merging, and adds coverage (unit + snapshot/benchmark-style) to lock in the new behavior.

Changes:

• Add @defer awareness to DocumentRewriter by introducing defer scopes/contexts and emitting rewritten deferred selections as ... @defer { ... }.
• Add extensive DocumentRewriterTests covering overlap/strip/push-down behavior for deferred selections (including nested/conditional cases).
• Add “benchmark parity” planning tests + snapshots and update Fusion benchmark project wiring (plus BenchmarkDotNet versioning).

Reviewed changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/HotChocolate/Fusion/test/Fusion.Utilities.Tests/Rewriters/DocumentRewriterTests.cs	Adds many new unit tests asserting correct @defer rewrite semantics (strip/push-down/preserve).
src/HotChocolate/Fusion/test/Fusion.Execution.Tests/Planning/FusionBenchmarkTests.cs	Adds snapshot-based planning tests intended to stay in sync with benchmark inputs.
src/HotChocolate/Fusion/test/Fusion.Execution.Tests/Planning/__snapshots__/FusionBenchmarkTests.Simple_Query_With_Requirements.yaml	New snapshot for the “simple query” benchmark-planning test.
src/HotChocolate/Fusion/test/Fusion.Execution.Tests/Planning/__snapshots__/FusionBenchmarkTests.Conditional_Redundancy_Query.yaml	New snapshot for the “conditional redundancy” benchmark-planning test.
src/HotChocolate/Fusion/test/Fusion.Execution.Tests/Planning/__snapshots__/FusionBenchmarkTests.Complex_Query.yaml	New snapshot for the “complex query” benchmark-planning test.
src/HotChocolate/Fusion/src/Fusion.Utilities/Rewriters/DocumentRewriter.cs	Implements defer scoping, back-references, and deferred selection emission.
src/HotChocolate/Fusion/HotChocolate.Fusion.slnx	Updates benchmark project path to renamed csproj.
src/HotChocolate/Fusion/benchmarks/Fusion.Execution.Benchmarks/OperationPlannerBenchmark.cs	Adds planner benchmark that uses rewritten documents.
src/HotChocolate/Fusion/benchmarks/Fusion.Execution.Benchmarks/OperationCompilerBenchmark.cs	Adds compiler benchmark (+ dotMemory diagnoser).
src/HotChocolate/Fusion/benchmarks/Fusion.Execution.Benchmarks/InlineFragmentOperationRewriterBenchmark.cs	Adds benchmark for inline-fragment operation rewriting.
src/HotChocolate/Fusion/benchmarks/Fusion.Execution.Benchmarks/HotChocolate.Fusion.Execution.Benchmarks.csproj	Adds dotMemory package + missing Fusion.Composition reference; reflects renamed project file.
src/HotChocolate/Fusion/benchmarks/Fusion.Execution.Benchmarks/FusionBenchmarkBase.cs	Introduces shared schema/document builders used by new benchmarks.
src/HotChocolate/Fusion/benchmarks/Fusion.Execution.Benchmarks/DocumentRewriterBenchmark.cs	Adds benchmark for DocumentRewriter.
src/Directory.Packages.props	Updates BenchmarkDotNet version and adds dotMemory package version.
src/All.slnx	Updates benchmark project path to renamed csproj.

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