Fix SchemaParser to handle semantically invalid type usage

[tobias-tengler]

No description provided.

[Copilot]

Pull request overview

This PR hardens schema parsing so that semantically invalid type usage (e.g., using an input object type in an output field position, even when wrapped in list/non-null) is detected early with clearer errors, and prevents follow-on schema validation noise when parsing already failed.

Changes:

• Update SchemaParser to validate input/output type semantics via IsInputType() / IsOutputType() (instead of relying on interface casts that wrappers can satisfy even when the named type is invalid).
• Add Fusion composition tests covering invalid type usage for fields, input object fields, arguments, and directive arguments.
• Skip schema validation in SourceSchemaParser when parsing has already produced errors to avoid cascading validation errors.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/HotChocolate/Mutable/src/Types.Mutable/Serialization/SchemaParser.cs	Enforces semantic input/output type correctness when building/merging fields and arguments.
src/HotChocolate/Fusion/test/Fusion.Composition.Tests/SourceSchemaParserTests.cs	Adds regression tests ensuring clear errors for invalid type usage and no cascading validation logs.
src/HotChocolate/Fusion/src/Fusion.Composition/SourceSchemaParser.cs	Avoids running schema validation when parsing already logged errors.

Comments suppressed due to low confidence (1)

src/HotChocolate/Fusion/test/Fusion.Composition.Tests/SourceSchemaParserTests.cs:128

• Assert.DoesNotContain(log, ...) is redundant after var entry = Assert.Single(log); (the log is already proven to have exactly one entry). Removing the extra assertion will simplify the test without reducing coverage.

        Assert.True(result.IsFailure);
        var entry = Assert.Single(log);
        Assert.Equal(
            "Invalid GraphQL in source schema. Exception message: "
            + "The field 'Query.exportFoos' must return an output type..",
            entry.Message);
        Assert.DoesNotContain(log, e => e.Code == "HCV0001");
    }

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