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.bat

@@ -0,0 +1,61 @@
+@echo off
+REM Helper script to set up .env file for Docker usage on Windows
+
+echo Setting up .env file for Gemini MCP Server Docker...
+
+REM Get the current working directory (absolute path)
+set CURRENT_DIR=%CD%
+
+REM Check if .env already exists
+if exist .env (
+    echo Warning: .env file already exists! Skipping creation.
+    echo.
+) else (
+    REM Create the .env file
+    (
+    echo # Gemini MCP Server Docker Environment Configuration
+    echo # Generated on %DATE% %TIME%
+    echo.
+    echo # The absolute path to your project root on the host machine
+    echo # This should be the directory containing your code that you want to analyze
+    echo WORKSPACE_ROOT=%CURRENT_DIR%
+    echo.
+    echo # Your Gemini API key ^(get one from https://makersuite.google.com/app/apikey^)
+    echo # IMPORTANT: Replace this with your actual API key
+    echo GEMINI_API_KEY=your-gemini-api-key-here
+    echo.
+    echo # Optional: Set logging level ^(DEBUG, INFO, WARNING, ERROR^)
+    echo # LOG_LEVEL=INFO
+    ) > .env
+    echo.
+    echo Created .env file
+    echo.
+)
+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   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.