build: add docker support

- Add Dockerfile for containerized deployment
- Add .drone.yml for CI/CD pipeline configuration
- Add docker and docker-run targets to Makefile
- Configure port 8080 binding and persistent volume mount

Dockerfile

@@ -0,0 +1,68 @@
+# Multi-stage build for Aethera
+# Stage 1: Build frontend assets
+FROM oven/bun:1 AS frontend-builder
+
+WORKDIR /app/frontend
+
+# Copy frontend package files
+COPY frontend/package.json frontend/bun.lock ./
+
+# Install dependencies
+RUN bun install --frozen-lockfile
+
+# Copy frontend source code
+COPY frontend/ ./
+
+# Build frontend assets
+RUN bun run build
+
+# Stage 2: Build Go binary
+FROM golang:1.25-alpine AS backend-builder
+
+WORKDIR /app
+
+# Install build dependencies
+RUN apk add --no-cache git
+
+# Copy go mod files
+COPY backend/go.mod backend/go.sum ./
+
+# Download Go dependencies
+RUN go mod download
+
+# Copy backend source code
+COPY backend/ ./
+
+# Copy frontend assets from previous stage
+COPY --from=frontend-builder /app/frontend/public/dist ./public/dist
+COPY --from=frontend-builder /app/frontend/public/index.html ./public/
+COPY --from=frontend-builder /app/frontend/public/pages ./public/pages
+
+# Build the Go binary
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-w -s" -o aethera ./cmd
+
+# Stage 3: Create minimal runtime image
+FROM alpine:3.21
+
+# Install ca-certificates for HTTPS calls
+RUN apk add --no-cache ca-certificates
+
+WORKDIR /app
+
+# Copy the binary from the builder stage
+COPY --from=backend-builder /app/aethera .
+
+# Copy static assets
+COPY --from=backend-builder /app/public ./public
+
+# Create data directory
+RUN mkdir -p /app/data
+
+# Expose the default port
+EXPOSE 8080
+
+# Set the entrypoint
+ENTRYPOINT ["./aethera"]
+
+# Default command with recommended production settings
+CMD ["--listen", "0.0.0.0", "--port", "8080", "--data-dir", "/app/data"]