Adds DOCX and Markdown export functionality

Introduces a modular exporter pattern supporting DOCX and Markdown formats
by implementing Exporter interfaces and restructuring application logic.

Enhances CI to install UPX for binary compression, excluding recent macOS
binaries due to compatibility issues.

Enables CGO when building binaries for all platforms, addressing potential
cross-platform compatibility concerns.

Bumps version to 0.1.1.

internal/exporters/factory.go

@@ -0,0 +1,63 @@
+// Package exporters provides implementations of the Exporter interface
+// for converting Articulate Rise courses into various file formats.
+package exporters
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/kjanat/articulate-parser/internal/interfaces"
+	"github.com/kjanat/articulate-parser/internal/services"
+)
+
+// Factory implements the ExporterFactory interface.
+// It creates appropriate exporter instances based on the requested format.
+type Factory struct {
+	// htmlCleaner is used by exporters to convert HTML content to plain text
+	htmlCleaner *services.HTMLCleaner
+}
+
+// NewFactory creates a new exporter factory.
+// It takes an HTMLCleaner instance that will be passed to the exporters
+// created by this factory.
+//
+// Parameters:
+//   - htmlCleaner: Service for cleaning HTML content in course data
+//
+// Returns:
+//   - An implementation of the ExporterFactory interface
+func NewFactory(htmlCleaner *services.HTMLCleaner) interfaces.ExporterFactory {
+	return &Factory{
+		htmlCleaner: htmlCleaner,
+	}
+}
+
+// CreateExporter creates an exporter for the specified format.
+// It returns an appropriate exporter implementation based on the format string.
+// Format strings are case-insensitive.
+//
+// Parameters:
+//   - format: The desired export format (e.g., "markdown", "docx")
+//
+// Returns:
+//   - An implementation of the Exporter interface if the format is supported
+//   - An error if the format is not supported
+func (f *Factory) CreateExporter(format string) (interfaces.Exporter, error) {
+	switch strings.ToLower(format) {
+	case "markdown", "md":
+		return NewMarkdownExporter(f.htmlCleaner), nil
+	case "docx", "word":
+		return NewDocxExporter(f.htmlCleaner), nil
+	default:
+		return nil, fmt.Errorf("unsupported export format: %s", format)
+	}
+}
+
+// GetSupportedFormats returns a list of all supported export formats.
+// This includes both primary format names and their aliases.
+//
+// Returns:
+//   - A string slice containing all supported format names
+func (f *Factory) GetSupportedFormats() []string {
+	return []string{"markdown", "md", "docx", "word"}
+}