Add CI/CD pipeline with Gitea Actions and Docker support

- Create Dockerfile for server with multi-stage build
- Create Dockerfile for agent with multi-stage build
- Set up Gitea Actions workflow to automatically build and release binaries
- Build for all platforms: Linux (amd64/arm64), macOS (amd64/arm64), Windows (amd64)
- Generate checksums for all release artifacts
- Include Docker image building in CI/CD pipeline
- Add release upload script for manual Gitea releases
- Add comprehensive RELEASE.md documentation

Dockerfile.server

@@ -0,0 +1,48 @@
+# Multi-stage build for nerd-monitor server
+FROM golang:1.24.4-alpine AS builder
+
+WORKDIR /app
+
+# Install build dependencies
+RUN apk add --no-cache git make
+
+# Copy go mod files
+COPY go.mod go.sum ./
+
+# Download dependencies
+RUN go mod download
+
+# Copy source code
+COPY . .
+
+# Generate templ templates
+RUN go run github.com/a-h/templ/cmd/templ@latest generate
+
+# Build the server binary
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-w -s" -o nerd-monitor-server ./cmd/server
+
+# Runtime stage
+FROM alpine:latest
+
+WORKDIR /app
+
+# Install ca-certificates for HTTPS
+RUN apk add --no-cache ca-certificates
+
+# Copy binary from builder
+COPY --from=builder /app/nerd-monitor-server .
+
+# Create non-root user
+RUN addgroup -D appgroup && adduser -D appuser -G appgroup
+USER appuser
+
+# Expose port
+EXPOSE 8080
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD wget --quiet --tries=1 --spider http://localhost:8080/login || exit 1
+
+# Run the server
+ENTRYPOINT ["./nerd-monitor-server"]
+CMD ["-addr", "0.0.0.0", "-port", "8080"]