feat: add Docker support for cross-platform easy setup

Implements comprehensive Docker support to eliminate Python version and dependency concerns.
Users can now run the MCP server in a container with automatic path translation between
host and container filesystems.

Key features:
- Dockerfile with multi-architecture support (amd64/arm64)
- Automatic path translation using WORKSPACE_ROOT environment variable
- Setup scripts for all platforms (Bash, CMD, PowerShell)
- GitHub Actions workflow for automated Docker Hub publishing
- Secure non-root container execution
- Read-only volume mounts by default

The setup process is now simplified to:
1. Run setup-docker-env script to generate .env and Claude config
2. Build the Docker image
3. Copy generated config to Claude Desktop

No Python installation or virtual environment management required.

Fixes #3

Co-Authored-By: Claude <noreply@anthropic.com>

setup-docker-env.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+# Helper script to set up .env file for Docker usage
+
+echo "Setting up .env file for Gemini MCP Server Docker..."
+
+# Get the current working directory (absolute path)
+CURRENT_DIR=$(pwd)
+
+# Check if .env already exists
+if [ -f .env ]; then
+    echo "⚠️  .env file already exists! Skipping creation."
+    echo ""
+else
+    # Create the .env file
+    cat > .env << EOF
+# Gemini MCP Server Docker Environment Configuration
+# Generated on $(date)
+
+# The absolute path to your project root on the host machine
+# This should be the directory containing your code that you want to analyze
+WORKSPACE_ROOT=$CURRENT_DIR
+
+# Your Gemini API key (get one from https://makersuite.google.com/app/apikey)
+# IMPORTANT: Replace this with your actual API key
+GEMINI_API_KEY=your-gemini-api-key-here
+
+# Optional: Set logging level (DEBUG, INFO, WARNING, ERROR)
+# LOG_LEVEL=INFO
+EOF
+    echo "✅ Created .env file"
+    echo ""
+fi
+echo "Next steps:"
+echo "1. Edit .env and replace 'your-gemini-api-key-here' with your actual Gemini API key"
+echo "2. Run 'docker build -t gemini-mcp-server .' to build the Docker image"
+echo "3. Copy this configuration to your Claude Desktop config:"
+echo ""
+echo "===== COPY BELOW THIS LINE ====="
+echo "{"
+echo "  \"mcpServers\": {"
+echo "    \"gemini\": {"
+echo "      \"command\": \"docker\","
+echo "      \"args\": ["
+echo "        \"run\","
+echo "        \"--rm\","
+echo "        \"-i\","
+echo "        \"--env-file\", \"$CURRENT_DIR/.env\","
+echo "        \"-v\", \"$CURRENT_DIR:/workspace:ro\","
+echo "        \"gemini-mcp-server:latest\""
+echo "      ]"
+echo "    }"
+echo "  }"
+echo "}"
+echo "===== COPY ABOVE THIS LINE ====="
+echo ""
+echo "Config file location:"
+echo "  macOS: ~/Library/Application Support/Claude/claude_desktop_config.json"
+echo "  Windows: %APPDATA%\\Claude\\claude_desktop_config.json"
+echo ""
+echo "Note: The configuration above mounts the current directory ($CURRENT_DIR)"
+echo "as the workspace. You can change this path to any project directory you want to analyze."