Add Go CLI with container expansion parser and development server

- Implement Go-based CLI for build-time HTML enhancement
- Add container expansion: div.insertr auto-expands to viable children
- Create servedev command with live development workflow
- Add Air configuration for automatic rebuilds and serving
- Enable transition from runtime JS to build-time enhancement approach

insertr-cli/pkg/parser/id_generator.go

@@ -0,0 +1,177 @@
+package parser
+
+import (
+	"crypto/sha1"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+// IDGenerator generates unique content IDs for elements
+type IDGenerator struct {
+	usedIDs map[string]bool
+}
+
+// NewIDGenerator creates a new ID generator
+func NewIDGenerator() *IDGenerator {
+	return &IDGenerator{
+		usedIDs: make(map[string]bool),
+	}
+}
+
+// Generate creates a content ID for an HTML element
+func (g *IDGenerator) Generate(node *html.Node) string {
+	context := g.getSemanticContext(node)
+	purpose := g.getPurpose(node)
+	content := g.getContentSample(node)
+
+	baseID := g.createBaseID(context, purpose, content)
+	return g.ensureUnique(baseID)
+}
+
+// getSemanticContext determines the semantic context from parent elements
+func (g *IDGenerator) getSemanticContext(node *html.Node) string {
+	// Walk up the tree to find semantic containers
+	parent := node.Parent
+	for parent != nil && parent.Type == html.ElementNode {
+		classes := getClasses(parent)
+
+		// Check for common semantic section classes
+		for _, class := range []string{"hero", "services", "nav", "navbar", "footer", "about", "contact", "testimonial"} {
+			if containsClass(classes, class) {
+				return class
+			}
+		}
+
+		// Check for semantic HTML elements
+		switch parent.Data {
+		case "nav":
+			return "nav"
+		case "header":
+			return "header"
+		case "footer":
+			return "footer"
+		case "main":
+			return "main"
+		case "aside":
+			return "aside"
+		}
+
+		parent = parent.Parent
+	}
+
+	return "content"
+}
+
+// getPurpose determines the purpose/role of the element
+func (g *IDGenerator) getPurpose(node *html.Node) string {
+	tag := strings.ToLower(node.Data)
+	classes := getClasses(node)
+
+	// Check for specific CSS classes that indicate purpose
+	for _, class := range classes {
+		switch {
+		case strings.Contains(class, "title"):
+			return "title"
+		case strings.Contains(class, "headline"):
+			return "headline"
+		case strings.Contains(class, "description"):
+			return "description"
+		case strings.Contains(class, "subtitle"):
+			return "subtitle"
+		case strings.Contains(class, "cta"):
+			return "cta"
+		case strings.Contains(class, "button"):
+			return "button"
+		case strings.Contains(class, "logo"):
+			return "logo"
+		case strings.Contains(class, "lead"):
+			return "lead"
+		}
+	}
+
+	// Infer purpose from HTML tag
+	switch tag {
+	case "h1":
+		return "title"
+	case "h2":
+		return "subtitle"
+	case "h3", "h4", "h5", "h6":
+		return "heading"
+	case "p":
+		return "text"
+	case "a":
+		return "link"
+	case "button":
+		return "button"
+	default:
+		return "content"
+	}
+}
+
+// getContentSample gets a sample of content for ID generation
+func (g *IDGenerator) getContentSample(node *html.Node) string {
+	text := extractTextContent(node)
+
+	// Clean and normalize text
+	text = strings.ToLower(text)
+	text = regexp.MustCompile(`[^a-z0-9\s]+`).ReplaceAllString(text, "")
+	text = regexp.MustCompile(`\s+`).ReplaceAllString(text, " ")
+	text = strings.TrimSpace(text)
+
+	// Take first few words
+	words := strings.Fields(text)
+	if len(words) > 3 {
+		words = words[:3]
+	}
+
+	return strings.Join(words, "-")
+}
+
+// createBaseID creates the base ID from components
+func (g *IDGenerator) createBaseID(context, purpose, content string) string {
+	parts := []string{}
+
+	// Add context if meaningful
+	if context != "content" {
+		parts = append(parts, context)
+	}
+
+	// Add purpose
+	parts = append(parts, purpose)
+
+	// Add content sample if available and meaningful
+	if content != "" && content != purpose {
+		parts = append(parts, content)
+	}
+
+	baseID := strings.Join(parts, "-")
+
+	// Clean up the ID
+	baseID = regexp.MustCompile(`-+`).ReplaceAllString(baseID, "-")
+	baseID = strings.Trim(baseID, "-")
+
+	// Ensure it's not empty
+	if baseID == "" {
+		baseID = "content"
+	}
+
+	return baseID
+}
+
+// ensureUnique makes sure the ID is unique by adding a suffix if needed
+func (g *IDGenerator) ensureUnique(baseID string) string {
+	if !g.usedIDs[baseID] {
+		g.usedIDs[baseID] = true
+		return baseID
+	}
+
+	// If base ID is taken, add a hash suffix
+	hash := fmt.Sprintf("%x", sha1.Sum([]byte(baseID)))[:6]
+	uniqueID := fmt.Sprintf("%s-%s", baseID, hash)
+
+	g.usedIDs[uniqueID] = true
+	return uniqueID
+}