Fix CI build/deploy/smoke pipeline for the self-hosted qa runner (#3)

## Summary
- Fix a chain of QA CI issues: Docker build/health-check flakiness, NuGet vuln pins, then adds the post-deploy integration + Playwright smoke suite and works through everything needed to make it actually run on the self-hosted `qa` runner (musl/Alpine job container, no node/dotnet/curl preinstalled, docker-outside-of-docker networking).
- Adds a fixed dev/QA seed admin user + fixed Development environment API key so integration tests and e2e specs have a stable target.
- Pins Aspire's `AppHost.cs` ports/credentials to match the docker-compose local dev defaults.
- Adds `tests/api/MicCheck.Api.Tests.Integration` coverage for disabled flags, environment-document bootstrap, identity override precedence, auth login, and unauthorized access; adds a Playwright e2e suite under `src/admin/e2e` (login, nav, context selection, features CRUD/toggle).
- Adds a `smoke-qa` CI job that runs both suites against the just-deployed QA stack, working around: no curl/node/dotnet on the bare runner, musl vs glibc (Playwright browsers run via the official `mcr.microsoft.com/playwright` image instead), and the runner's job-container network isolation (reach the QA stack via the docker bridge gateway IP; `docker cp` instead of a bind mount to get files into the playwright container, since paths don't cross the docker-outside-of-docker boundary).

## Test plan
- [x] Unit tests pass (dotnet test tests/api/MicCheck.Api.Tests.Unit, 243 passed)
- [x] API integration suite passes against the real QA stack in CI
- [x] Playwright e2e suite passes against the real QA stack in CI (verified 3/3 locally against a real dev API + vite server for the flakiest spec)
- [x] Full CI pipeline (build → deploy-qa → smoke-qa) green end to end on the qa runner

Reviewed-on: #3

src/MicCheck.AppHost/AppHost.cs

@@ -1,14 +1,26 @@
 var builder = DistributedApplication.CreateBuilder(args);
 
-var postgres = builder.AddPostgres("postgres").WithDataVolume("miccheck-pgdata").WithPgAdmin();
+// Pinned to match tests/api/MicCheck.Api.Tests.Integration/local.runsettings and
+// src/admin's docker-compose defaults, so those fixed targets work whether the
+// stack is run via `docker compose` or via this AppHost.
+var postgresUser = builder.AddParameter("postgres-username", "miccheck");
+var postgresPassword = builder.AddParameter("postgres-password", "password", secret: true);
+
+var postgres = builder.AddPostgres("postgres", postgresUser, postgresPassword, port: 5432)
+    .WithDataVolume("miccheck-pgdata")
+    .WithPgAdmin();
 
 var miccheckDb = postgres.AddDatabase("miccheck");
 
-var api = builder.AddProject<Projects.MicCheck_Api>("api").WithReference(miccheckDb).WaitFor(miccheckDb);
+var api = builder.AddProject<Projects.MicCheck_Api>("api")
+    .WithReference(miccheckDb)
+    .WaitFor(miccheckDb)
+    .WithHttpEndpoint(port: 5000, name: "http");
 
 builder.AddViteApp("admin", "../admin", "serve")
     .WithReference(api)
     .WaitFor(api)
+    .WithHttpEndpoint(port: 5173, name: "http")
     .WithExternalHttpEndpoints();
 
 builder.Build().Run();

src/MicCheck.AppHost/MicCheck.AppHost.csproj

@@ -8,6 +8,7 @@
   <ItemGroup>
     <PackageReference Include="Aspire.Hosting.JavaScript" Version="13.4.2" />
     <PackageReference Include="Aspire.Hosting.PostgreSQL" Version="13.4.0" />
+    <PackageReference Include="MessagePack" Version="2.5.302" />
   </ItemGroup>
 
   <PropertyGroup>