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.agent

@@ -0,0 +1,34 @@
+# Multi-stage build for nerd-monitor agent
+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 . .
+
+# Build the agent binary (no templ needed for agent)
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-w -s" -o nerd-monitor-agent ./cmd/agent
+
+# Runtime stage
+FROM alpine:latest
+
+WORKDIR /app
+
+COPY --from=builder /app/nerd-monitor-agent .
+
+# Create non-root user
+RUN addgroup -D appgroup && adduser -D appuser -G appgroup
+USER appuser
+
+# Run the agent
+ENTRYPOINT ["./nerd-monitor-agent"]
+CMD ["--server", "localhost:8080"]