Add explicit Native AOT/trim compatibility and CI smoke publish for Semantic

[Copilot]

This PR makes Native AOT/trimming support explicit and continuously validated for Semantic while preserving the existing public API and target framework. It also adds a minimal executable smoke app that exercises the core semantic builders under AOT publish.

• Library AOT/trim contract

  • Updated Semantic/Semantic.csproj to declare compatibility and enable analysis:
    • IsAotCompatible
    • IsTrimmable
    • EnableTrimAnalyzer

• Native AOT smoke app

  • Added NativeAotSmoke console project referencing Semantic.
  • Smoke app executes representative paths for:
    • PatternMatchesBuilder
    • SlidingWindowBuilder
    • MovingAverageBuilder
  • Uses simple runtime assertions to fail fast if behavior regresses.

• CI enforcement

  • Extended .github/workflows/ci.yml with a Native AOT publish step for the smoke app (linux-x64, trimmed + AOT).
  • Added required Linux prerequisites for AOT toolchain install in workflow.

• Related low-risk cleanup

  • Removed unused using System.Buffers; from Semantic/Sequences/PatternMatches.cs.

<!-- Semantic/Semantic.csproj -->
<PropertyGroup>
  <IsAotCompatible>true</IsAotCompatible>
  <IsTrimmable>true</IsTrimmable>
  <EnableTrimAnalyzer>true</EnableTrimAnalyzer>
</PropertyGroup>

# .github/workflows/ci.yml
- name: Native AOT smoke publish
  run: >
    dotnet publish NativeAotSmoke/NativeAotSmoke.csproj
    --configuration Release
    -r linux-x64
    -p:PublishAot=true
    -p:PublishTrimmed=true

Original prompt

Implement Native AOT / trimming-friendly improvements in Franchef/Semantic.NET on branch chore/native-aot-trim-friendly and open a pull request back to main.

Context:

• The repository is a C# library (Semantic) with semantic utilities under Semantic/Sequences and Semantic/Statistic.
• Current code appears largely trim-safe already: no obvious reflection, runtime type discovery, dynamic code generation, or linker-hostile patterns were found in the core library.
• The goal is to make compatibility explicit and enforceable so the library can be safely used in high-performance, cloud-native Native AOT environments.

Requested changes:

1. Update the library project configuration in Semantic/Semantic.csproj to explicitly enable Native AOT / trimming compatibility analysis.

   • Add appropriate MSBuild properties such as:
     • <IsAotCompatible>true</IsAotCompatible>
     • <IsTrimmable>true</IsTrimmable>
     • <EnableTrimAnalyzer>true</EnableTrimAnalyzer>
   • Keep the project aligned with the current target framework unless a change is necessary.

2. Add a minimal Native AOT smoke test sample/app in the repository that references the Semantic library and exercises the main semantic extensions:

   • PatternMatchesBuilder
   • SlidingWindowBuilder
   • MovingAverageBuilder
     The sample should be suitable for publish-time validation with AOT/trimming (for example via PublishAot=true and PublishTrimmed=true).

3. Add CI validation for the Native AOT scenario.

   • Extend the existing workflow(s) or add a dedicated workflow so the repo verifies that the smoke test app can publish successfully with trimming/AOT enabled.
   • Keep the CI change focused and maintainable.

4. Clean up any low-risk code issues found during review that support the goal.

   • For example, remove obviously unused usings if encountered (such as the unused using System.Buffers; in Semantic/Sequences/PatternMatches.cs if still present).

Implementation guidance:

• Preserve the library’s existing public API unless a change is required.
• Prefer minimal, focused changes over broad refactors.
• If the repo already has workflow or sample app conventions, follow them.
• Add or update tests/documentation only as needed to support the new AOT compatibility work.

Deliverable:

• Commit the changes on the working branch and open a PR from chore/native-aot-trim-friendly to main with a concise title and summary of the AOT/trim-friendly improvements.

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: in this repo, for Native AOT Compatibility: Ensure all semantic extensions are "Trim-friendly" so the library can be used in high-performance, cloud-native environments.

Assistant: This repo already looks largely Native AOT / trimming-safe, and I don’t see obvious reflection-heavy or linker-hostile patterns in the current semantic extensions.

What I found:

• No obvious use of:
  • System.Reflection
  • Activator.CreateInstance
  • Type.GetType
  • dynamic code generation
  • expression compilation
  • serializer metadata patterns that usually need trim annotations
• The public API is mostly simple generic builders and interfaces, which is good for trimming/AOT.

Key files reviewed:

• Semantic/Sequences/PatternMatches.cs
• Semantic/Sequences/PatternMatchesBuilder.cs
• Semantic/Sequences/SlidingWindow.cs
• Semantic/Sequences/SlidingWindowBuilder.cs
• Semantic/Statistic/MovingAverage.cs
• Semantic/Statistic/MovingAverageBuilder.cs
• Semantic/Statistic/MovingAverageCustomStep.cs
• Semantic/Semantic.csproj

Assessment

Current status: likely already trim-friendly by implementation.

The code uses:

• generics
• arrays
• EqualityComparer<T>.Default
• events
• basic collection and LINQ usage

Those are generally fine for Native AOT.

Main improvement I recommend

The repo is missing explicit trimming/AOT validation in the project configuration and CI.
So the best next step is to make compatibility intentional and enforceable, not just incidental.

Suggested changes

1. Enable trim-analysis warnings in Semantic/Semantic.csproj
   Add properties like:
   • IsAotCompatible
   • IsTrimmable
   • EnableTrimAnalyzer

Example:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net10.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <IsAotCompatible>true</IsAotCompatible>
    <IsTrimmable>true</IsTrimmable>
    <EnableTrimAnalyzer>true</EnableTrimAnalyzer>
  </PropertyGroup>

  <ItemGroup>
    <Folder Include="Sequences/" />
    <Folder Include="Statistic/" />
  </ItemGroup>

</Project>

2. Add a small Native AOT smoke test app
   Create a sample app that:
   • references Semantic
   • uses PatternMatchesBuilder, `SlidingW...

This pull request was created from Copilot chat.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.95%. Comparing base (e4d368d) to head (587a87a).

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #22   +/-   ##
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  Coverage   95.95%   95.95%           
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  Files           7        7           
  Lines          99       99           
  Branches       20       20           
=======================================
  Hits           95       95           
  Misses          2        2           
  Partials        2        2           

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