Add event-model viewer and Critter Stack samples

[woksin]

Added

• Event-model samples for viewing an Arc + Chronicle coffee counter from the running application or CLI, and generating a reviewable Screenplay starting point from an original Marten + Wolverine community kitchen. (Add end-to-end event-model viewer and Critter Stack generation samples #622)

[woksin]

Verification

Local checks passed on macOS with .NET SDK 10.0.401 and Node 26.8.1. GitHub Actions supplies the Ubuntu/Node 24 check; that platform combination was not run locally.

• dotnet build EventModeling/EventModeling.slnx -c Release -warnaserror: both new samples, zero warnings and errors.
• CI's full Samples.slnx Debug build (including proxy generation) and Release build with --no-restore -p:CratisProxiesOutputPath=: passed. Existing Library/Quickstart analyzer and dependency warnings remain; no repository-wide warning suppressions were added.
• All seven CI-listed Debug .NET specification projects: 28 passed.
• Arc/React, Library/Lending, Library/Members: yarn lint:ci, yarn compile, yarn test --passWithNoTests, and yarn build passed. Arc/React has two frontend tests; the two Library workspaces currently have none.
• Capstone: npm ci, npm run lint, and npm run build passed.
• node scripts/validate-samples.mjs and git diff --check: passed.
• Both checked-in model versions passed cratis screenplay validate <file> --warnings-as-errors. The raw generated file needed no edits to validate.

Runtime and viewer checks

• Started Chronicle 19.29.2-development through the sample's Compose file. The development hierarchy endpoint returned the embedded documents, and the coffee order command returned isSuccess: true.
• Started PostgreSQL 17.6-alpine through the kitchen Compose file. Planning, preparation, and serving requests succeeded; the projected card changed from unserved/zero portions to served/12 portions. The not-ready serving request left the card unserved.
• CLI 3.24.0 cratis view hosted the embedded model; its root HTML and JavaScript/CSS assets returned HTTP 200.
• Screenplay 4.48.0's MCP visualize-model returned the raw kitchen model, and its bundled MCP App was rendered and visually inspected in a local Chrome host. VS Code and an actual AI chat client were not exercised. The hosted Studio viewer was checked for availability, not an end-to-end upload.

Review focus

The raw kitchen model is intentionally untouched. It validates, but it does not recover the direct Marten command/event links, the aggregate-handler decision, or the original transaction/transport semantics. It places events and commands in disconnected slices and points the serving handler at the HTTP wrapper. The README calls this out, and the reviewed model is separate rather than quietly replacing the raw result.

The Arc host contains a narrow workaround for the pinned packages: remove the convention-bound IChronicleConnection so Chronicle constructs its configured connection. The kitchen includes WolverineFx.RuntimeCompilation, required by this Wolverine version for its dynamic handler compilation.

Please leave this PR unmerged, as requested. Assigned to woksin; no self-review request was sent.