Release v4.209.0

Added

• cratis run and sandbox specifications now execute inline and file rule bodies (property and concept validation rules) in an isolated body worker process, instead of skipping them. Bodies outside the supported subset are refused with an explicit diagnostic. (part of #891)
• Rendered read-model specifications can now seed read models with composite keys, including seeds that later events update. (#874)
• Keyed observable optional read-model lookups now render. (part of #58)
• Documented the Stage. repository model, its naming rules and its direction dependency rules. (#787)

Changed

• Requires Chronicle 19.112.1 or later. Rendered applications now pin Chronicle 19.112.1 and Arc 22.143.0. (part of #874)
• Rendered applications pin Microsoft.Extensions.Telemetry.Abstractions 10.11.0, and its Microsoft.Extensions.Compliance.Abstractions 10.11.0 dependency, to work around Cratis/Chronicle#5442.
• Members whose implementation body is not C# are now refused with STAGE-IMPL-LANGUAGE, including query performers that previously became stubs. Add a C# body to render them with the Cratis target. (part of #869)
• Generated inline command handlers and generation helpers now get readable, stable names instead of hash-based ones. (part of #850)
• The Stage host and the legacy model loader now load models that declare command reads protected, and run protected decisions safely on the default engine. Engines that cannot preserve protected reads refuse such a model with STAGE-ESM-044 instead of ignoring it. (#892)
• An event member whose type Stage can't render now degrades only the owners that depend on it, instead of refusing the whole render. Strict mode and unaudited newer ESM versions still refuse. (#832)
• Specifications that reach Translate commands are now refused with STAGE-ESM-024. (#731)
• The Billing sample now uses the executable model: declarative productions replace the handler escape hatches, and invoice settlement is shown through an outstanding-balance read model. (#885)

Fixed

• Reaction bodies that return an EventForEventSourceId with an unproven payload, or that modify or pass @event by reference, are now refused with STAGE-ESM-037 instead of being admitted. (#893)
• Generated frontends now ignore Yarn install state (.yarn/) in .gitignore. (#741)