chore: add Docker deployment setup and health check wiring

- Add multi-stage Dockerfile for backend (SDK build → ASP.NET runtime,
  non-root user, /health HEALTHCHECK)
- Add docker-compose.dev.yml orchestrating extrudex-api + control-center-web
- Add deploy.sh convenience script wrapping docker compose up --build
- Wire ASP.NET health checks: AddHealthChecks().AddNpgSql() + MapHealthChecks("/health")
- Add backend .dockerignore (comprehensive pattern list)
- Exclude frontend/dist, frontend/node_modules, frontend/.angular from git

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/.dockerignore

@@ -0,0 +1,27 @@
+# Build artifacts
+bin/
+obj/
+
+# IDE / editor
+.vs/
+.vscode/
+*.user
+*.suo
+.idea/
+
+# Environment & secrets
+appsettings.Development.json
+.env
+.env.*
+
+# Docker
+Dockerfile
+.dockerignore
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Misc
+*.md
+*.log

backend/Dockerfile

@@ -0,0 +1,34 @@
+# ── Stage 1: Build ──────────────────────────────────────────
+FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build
+WORKDIR /src
+
+# Copy csproj first for layer caching — restores before copying source
+COPY Extrudex.csproj .
+RUN dotnet restore
+
+# Copy the rest of the source
+COPY . .
+RUN dotnet publish Extrudex.csproj \
+    -c Release \
+    -o /app/publish \
+    --no-restore
+
+# ── Stage 2: Runtime ────────────────────────────────────────
+FROM mcr.microsoft.com/dotnet/aspnet:9.0 AS runtime
+WORKDIR /app
+
+# Non-root user for security
+RUN adduser --disabled-password --gecos "" appuser
+USER appuser
+
+# Copy published output from build stage
+COPY --from=build /app/publish .
+
+# ASP.NET Core listens on 8080 by default in .NET 8+
+EXPOSE 8080
+
+# Health check against /health endpoint
+HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
+    CMD curl --fail http://localhost:8080/health || exit 1
+
+ENTRYPOINT ["dotnet", "Extrudex.dll"]

backend/Extrudex.csproj

@@ -9,6 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="AspNetCore.HealthChecks.NpgSql" Version="9.0.0" />
     <PackageReference Include="FluentValidation.DependencyInjectionExtensions" Version="12.1.1" />
     <PackageReference Include="Microsoft.EntityFrameworkCore" Version="9.0.3" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.3" />

backend/Program.cs

@@ -69,6 +69,10 @@ builder.Services.AddCors(options =>
 // ── SignalR (real-time printer updates) ────────────────────
 builder.Services.AddSignalR();
 
+// ── Health Checks ───────────────────────────────────────────
+builder.Services.AddHealthChecks()
+    .AddNpgSql(connectionString);
+
 var app = builder.Build();
 
 // ── Middleware ──────────────────────────────────────────────
@@ -85,6 +89,9 @@ app.MapControllers();
 // ── Hub Endpoints ───────────────────────────────────────────
 app.MapHub<PrinterHub>("/hubs/printer");
 
+// ── Health Check Endpoint ──────────────────────────────────
+app.MapHealthChecks("/health");
+
 app.Run();
 
 // Helper: builds a connection string from individual env vars.