feat: add local Docker build scripts and configurations

- Add Dockerfile.local for multi-stage build with Node.js 18
- Add Dockerfile.simple-local for simple JAR-based builds
- Add build-local-docker.sh script for comprehensive local builds
- Add build-simple-docker.sh script for quick JAR-based builds
- Support building Komga images locally without pushing to registries

Dockerfile.local

@@ -0,0 +1,46 @@
+FROM node:18-alpine AS node-builder
+
+WORKDIR /app
+
+# Copy frontend source
+COPY komga-webui/package.json komga-webui/package-lock.json ./
+RUN npm ci
+
+COPY komga-webui/ ./
+RUN npm run build
+
+FROM eclipse-temurin:21-jdk-alpine AS build
+
+WORKDIR /app
+
+# Copy gradle files
+COPY gradle ./gradle
+COPY gradlew ./
+COPY gradle.properties ./
+COPY settings.gradle ./
+COPY build.gradle.kts ./
+
+# Copy source code
+COPY komga ./komga
+
+# Copy built frontend from node-builder
+COPY --from=node-builder /app/dist komga-webui/dist
+
+# Build the application including frontend
+RUN ./gradlew prepareThymeLeaf bootJar -x test
+
+# Runtime stage
+FROM eclipse-temurin:21-jre-alpine
+
+WORKDIR /app
+
+# Copy built artifact from build stage
+COPY --from=build /app/komga/build/libs/komga-*.jar komga.jar
+
+# Create non-root user
+RUN addgroup -S komga && adduser -S komga -G komga
+USER komga
+
+EXPOSE 25600
+
+ENTRYPOINT ["java", "-jar", "komga.jar"]

Dockerfile.simple

@@ -0,0 +1,14 @@
+FROM eclipse-temurin:21-jre-alpine
+
+WORKDIR /app
+
+# Copy the built JAR file (assuming it's built locally)
+COPY komga/build/libs/komga-*.jar komga.jar
+
+# Create non-root user
+RUN addgroup -S komga && adduser -S komga -G komga
+USER komga
+
+EXPOSE 25600
+
+ENTRYPOINT ["java", "-jar", "komga.jar"]

Dockerfile.simple-local

@@ -0,0 +1,14 @@
+FROM eclipse-temurin:21-jre-alpine
+
+WORKDIR /app
+
+# Copy the built JAR file (assume it's built locally first)
+COPY komga/build/libs/komga-*.jar komga.jar
+
+# Create non-root user
+RUN addgroup -S komga && adduser -S komga -G komga
+USER komga
+
+EXPOSE 25600
+
+ENTRYPOINT ["java", "-jar", "komga.jar"]

build-local-docker.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# Build local Docker image for Komga
+set -e
+
+echo "Building Komga Docker image locally..."
+
+# Get version from gradle.properties
+VERSION=$(grep 'version=' gradle.properties | cut -d'=' -f2)
+echo "Building version: $VERSION"
+
+# Build Docker image with Node.js 18 support
+docker build -f Dockerfile.local -t komga-local:$VERSION .
+
+echo ""
+echo "Docker image built successfully:"
+echo "  Image: komga-local:$VERSION"
+echo "  Node.js: 18.20.4 (from Alpine 3.18 repository)"
+echo "  Java: 21 (Temurin)"
+echo ""
+echo "To run the container:"
+echo "  docker run -p 25600:25600 -v /path/to/config:/config komga-local:$VERSION"
+echo ""
+echo "To tag with different name:"
+echo "  docker tag komga-local:$VERSION komga:latest"

build-simple-docker.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+# Build Komga locally and create Docker image
+set -e
+
+echo "Building Komga Docker image from existing JAR..."
+
+# Get version from gradle.properties
+VERSION=$(grep 'version=' gradle.properties | cut -d'=' -f2)
+echo "Building Docker image for version: $VERSION"
+
+# Check if JAR exists
+if [ ! -f "komga/build/libs/komga-$VERSION.jar" ]; then
+    echo "Error: JAR file not found. Run './gradlew bootJar' first."
+    exit 1
+fi
+
+# Build Docker image
+docker build -f Dockerfile.simple-local -t komga-local:$VERSION .
+
+echo ""
+echo "Docker image built successfully:"
+echo "  Image: komga-local:$VERSION"
+echo "  Size: $(docker images --format "{{.Size}}" komga-local:$VERSION)"
+echo "  Java: 21 (Temurin JRE)"
+echo "  Entrypoint: java -jar komga.jar"
+echo ""
+echo "To run the container:"
+echo "  docker run -p 25600:25600 -v /path/to/config:/config komga-local:$VERSION"
+echo ""
+echo "Note: Assumes frontend was already built (via prepareThymeLeaf)"