feat(sink): scaffold samples/WebhookSink minimal-API — app only (S0a)

[williamdewitt]

S0a of the WebhookSink artifact (epic #49). App project only — the smoke-test project is split into #53 to keep this within one agent run (the first attempt hit the 30-turn cap after also creating a test project). Design: docs/design/webhook-sink-design.md.

Acceptance criteria

• New project samples/WebhookSink/ — ASP.NET Core minimal-API, single-target net10.0, wired into Caliber.Webhooks.slnx (a /samples/ solution folder).
• <IsPackable>false</IsPackable>.
• ProjectReference to src/Caliber.Webhooks/Caliber.Webhooks.csproj. No new third-party packages (the scaffold needs none — just the framework reference).
• Endpoints: GET /healthz → 200 OK, and a placeholder GET / home page (plain text/HTML stub that names the sink). No capture / dashboard / fault-injection / signature code — later slices.
• Inherits the repo shell (nullable, warnings-as-errors, Meziantou) with zero new suppressions.

Definition of done

• dotnet build -c Release green across the solution, zero analyzer warnings.
• PR description shows the build output. The WebApplicationFactory smoke test for /healthz lands in the follow-up test(sink): WebApplicationFactory smoke test for samples/WebhookSink (S0b) #53.

Implementer notes

• Small, well-specified slice — implement directly with minimal exploration. The design is summarised above; no need to re-read the full docs bundle. Aim to finish well inside the turn budget.
• Keep Program.cs minimal-hosting; it's the seam S1 (capture) builds on. Add public partial class Program { } so test(sink): WebApplicationFactory smoke test for samples/WebhookSink (S0b) #53's WebApplicationFactory can reference it.
• risk:low (samples/**): PR gates on CI-green + a light human approval; does not auto-merge.

[williamdewitt]

@claude please implement this issue per its acceptance criteria and definition of done. Scaffold only — samples/WebhookSink minimal-API (net10.0), wired into the .slnx, IsPackable=false, a ProjectReference to Caliber.Webhooks, GET /healthz + a placeholder home page, and a WebApplicationFactory smoke test for /healthz. No capture/dashboard/fault-injection/signature code — those are later slices (S1–S4). Full context in docs/design/webhook-sink-design.md. Open a PR when green.

[claude]

Claude encountered an error after 10m 48s —— View job

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Implementation Plan

• Gather context (read design doc, existing project structure, conventions)
• Create samples/WebhookSink/WebhookSink.csproj (net10.0, IsPackable=false, ProjectReference + InternalsVisibleTo)
• Implement Program.cs with GET /healthz and placeholder GET / home page
• Wire WebhookSink into Caliber.Webhooks.slnx (added /samples/ folder)
• Create tests/WebhookSink.Tests/WebhookSink.Tests.csproj (xUnit v3, MTP, AwesomeAssertions, WebApplicationFactory)
• Write WebApplicationFactory smoke test for GET /healthz
• Wire tests project into solution (/tests/ folder)
• Add Microsoft.AspNetCore.Mvc.Testing v10.0.0 to Directory.Packages.props
• Run dotnet build -c Release — confirm green, zero analyzer warnings
• Run tests — confirm green
• Commit and push
• Open PR

[williamdewitt]

@claude re-running this now that it's trimmed to app-only (the test project moved to #53). Please implement directly with minimal exploration — it's a small, well-specified slice: create samples/WebhookSink (net10.0 minimal-API, IsPackable=false, ProjectReference to Caliber.Webhooks, a public partial class Program {} shim), add GET /healthz + a placeholder GET /, wire it into Caliber.Webhooks.slnx, confirm dotnet build -c Release is green with zero warnings, then commit/push and open the PR. No test project (that's #53).

[claude]

Claude finished @williamdewitt's task in 2m 41s —— View job • claude/issue-50-20260626-2211 • Create PR ➔

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Implementation Plan

• Gather context (read existing project conventions)
• Create samples/WebhookSink/WebhookSink.csproj (net10.0, IsPackable=false, ProjectReference)
• Create Program.cs with GET /healthz + placeholder GET / + public partial class Program {}
• Wire WebhookSink into Caliber.Webhooks.slnx (add /samples/ solution folder)
• Commit and push
• Open PR

What was created

samples/WebhookSink/WebhookSink.csproj — Microsoft.NET.Sdk.Web, net10.0, IsPackable=false, ProjectReference to src/Caliber.Webhooks, GenerateDocumentationFile=false (sample, not a shipped library).

samples/WebhookSink/Program.cs — minimal hosting with:

• GET /healthz → Results.Ok() (200)
• GET / → HTML stub naming the sink
• public partial class Program { } shim for test(sink): WebApplicationFactory smoke test for samples/WebhookSink (S0b) #53's WebApplicationFactory

Caliber.Webhooks.slnx — added /samples/ solution folder containing the new project.

Note: dotnet build -c Release could not be run in this sandbox — CI will verify the build is green with zero warnings. The changes strictly follow repo conventions (nullable, TreatWarningsAsErrors, Meziantou, Central Package Management, no new packages).

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