[woksin]

Changed

• The sample specification projects run on Cratis Specifications 5 and xUnit v3, and CI runs every spec project, including the Library apps' in-process specifications. (Migrate sample specifications to Specifications 5 and xUnit v3 #667)
• The Library AppHost now follows Chronicle's Aspire guidance: one MongoDB replica set for Chronicle storage and the read models, the slim development image, and the Workbench on port 35000 instead of a separate management port. (Library AppHost disagrees with Chronicle's Aspire docs on MongoDB and the management endpoint #668)

[woksin]

Reviewer notes

• Local gate mirroring build.yml's backend job (restore, Shop model check, Debug build, the 12 spec projects, Lending/Members/Shop.Rendered dotnet test, Release restore + build): pass. .github/scripts/run-specs.test.mjs: 12/12.
• Package pins: MongoDB.Driver 3.13.0, Cratis.Chronicle.XUnit.Integration.v3 19.111.0 (aligned with main's Chronicle 19.111 bump).
• Full review round 1 passed (no blocking findings); the one advisory (slnx indentation) is fixed in the last commit.
• No frontend changes. Debug builds regenerate some proxies with newer Arc output (sliceLocation); those were left out of this PR.
• no-release: samples ship nothing. Migrate sample specifications to Specifications 5 and xUnit v3 #667 and Library AppHost disagrees with Chronicle's Aspire docs on MongoDB and the management endpoint #668 will be closed by hand after merge.