Enforce compiler-semantic attributes in signature conformance (issue #19560)

[T-Gro]

Summary

Fixes #19560.

When an implementation file declares a compiler-semantic attribute (such as []) on a value or member, tooling does not consult the implementation when a corresponding .fsi signature file is present. This means attributes only on the impl are silently lost, changing the contract observed by consumers (inlining behaviour, dynamic dispatch, codegen).

This PR adds a signature conformance check that enforces these attributes must also appear in the signature, producing a clear error when they are missing.

Changes

• src/Compiler/Checking/SignatureConformance.fs – Added signatureEnforcedAttributes list and a loop in CheckOneImplVal that errors if the impl value has an enforced attribute but the signature does not.
• src/Compiler/FSComp.txt – New diagnostic message for the missing-attribute error.
• src/FSharp.Core/prim-types.fsi / src/FSharp.Core/nativeptr.fsi – Added missing [] declarations to the signature files to satisfy the new check.
• tests/FSharp.Compiler.ComponentTests/Conformance/Signatures/SignatureEnforcedAttributes.fs – New test file with 6 test cases covering the enforcement behavior.
• docs/release-notes/.FSharp.Compiler.Service/11.0.100.md – Release note entry.
• xlf files – Updated localization resource files with the new diagnostic string.

Testing

• 6 new component tests validate both positive (error raised) and negative (no spurious errors) scenarios.
• Existing signature conformance tests continue to pass.

[github-actions]

❗ Release notes required

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✅ Found changes and release notes in following paths:

Change path	Release notes path	Description
src/FSharp.Core	docs/release-notes/.FSharp.Core/11.0.100.md
src/Compiler	docs/release-notes/.FSharp.Compiler.Service/11.0.100.md

[auduchinok]

Thanks!