add docker configuration and gitea workflow for automated image builds

Introduce a multi-stage Dockerfile, docker-compose setup, and a Gitea Actions workflow to automate building and pushing images to the registry. The configuration includes an entrypoint script for persistent logging and a .dockerignore to optimize the build context.

Dockerfile

@@ -0,0 +1,29 @@
+# --- Build stage ---
+FROM golang:alpine AS builder
+
+WORKDIR /build
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-s -w" -o emly-api .
+
+# --- Runtime stage ---
+FROM alpine:latest
+
+RUN apk --no-cache add ca-certificates tzdata
+
+WORKDIR /app
+
+COPY --from=builder /build/emly-api .
+COPY --from=builder /build/internal/database/schema ./internal/database/schema
+COPY --from=builder /build/internal/handlers/templates ./internal/handlers/templates
+COPY docker/entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+RUN mkdir -p /logs
+
+EXPOSE 8080
+
+ENTRYPOINT ["/entrypoint.sh"]