Add lightweight EF Core hot-path sample

[balajibashyam]

Summary

Adds a minimal .NET 10 companion sample for the EF Core Advanced Modeling & Performance: Owned Types, Converters, JSON/Temporal Tables, Compiled Queries tutorial.

What's included

• New sample: ef-core/advanced-modeling-performance/ — 12 files

  • DTO projection with AsNoTracking
  • EF.CompileAsyncQuery for stable SKU lookups
  • Named EF Core 10 soft-delete query filter (SoftDeleteFilter)
  • ExecuteUpdateAsync for set-based stock restocking
  • ExecuteDeleteAsync for soft-delete purge
  • Stale tracked-entity proof after ExecuteUpdate
  • 8 deterministic xUnit v3 tests
  • SQLite in-memory isolation (no server, no Docker)

• Root README: New sample row in the table + ef-core/ tree entry

• GitHub Actions: New test-ef-core-hot-path job; path filters updated for both push and pull_request

Deliberately omitted (stays in the full tutorial)

SQL Server, PostgreSQL, temporal tables, JSON columns, owned/complex types, value converters, encryption, concurrency tokens, migrations, Testcontainers, split queries, logging/interceptors, benchmarking

Versions

• .NET SDK: 10.0.302
• Microsoft.EntityFrameworkCore.Sqlite: 10.0.11

Validation

• dotnet restore — passed
• dotnet build --configuration Release — passed (0 errors, 0 warnings)
• dotnet test --configuration Release — passed (8/8)
• Exact deterministic console output verified
• Security scan — clean
• Package baseline — 1 direct package
• No SQLite database file generated