feat: Implement syntactic sugar and site-specific discovery config

- Add syntactic sugar for container transformation: .insertr containers → children get .insertr
- Fix discovery auto-running when disabled with site-specific config loading
- Add comprehensive styling test examples for HTML attribute preservation
- Include test input for syntactic sugar validation
- Update discovery defaults to respect developer intent (disabled by default)

internal/content/discoverer.go

@@ -90,6 +90,7 @@ type FileDiscoveryResult struct {
 	ElementsEnhanced int
 	ContainersAdded  int
 	IndividualsAdded int
+	SugarTransformed int // Count of syntactic sugar transformations
 	Document         *html.Node
 }
 
@@ -124,7 +125,30 @@ func (disc *Discoverer) discoverNode(node *html.Node, result *FileDiscoveryResul
 		return
 	}
 
-	// Skip if already has insertr class
+	// Handle syntactic sugar: containers with .insertr class
+	if disc.hasInsertrClass(node) && disc.isGoodContainer(node) {
+		// Syntactic sugar transformation: remove .insertr from container, add to viable children
+		viableChildren := engine.FindViableChildren(node)
+		if len(viableChildren) >= 1 {
+			disc.removeInsertrClass(node) // Remove from container
+			for _, child := range viableChildren {
+				if !disc.hasInsertrClass(child) {
+					disc.addInsertrClass(child)
+					result.IndividualsAdded++
+					result.ElementsEnhanced++
+				}
+			}
+			result.ContainersAdded++
+			result.SugarTransformed++ // Track sugar transformations
+
+			// Don't process children since we just processed them
+			return
+		}
+		// If no viable children, leave .insertr on the element (individual editing)
+		return
+	}
+
+	// Skip if already has insertr class (individual editing elements)
 	if disc.hasInsertrClass(node) {
 		return
 	}
@@ -258,6 +282,18 @@ func (disc *Discoverer) addInsertrClass(node *html.Node) {
 	disc.setClasses(node, classes)
 }
 
+// removeInsertrClass removes the insertr class from a node
+func (disc *Discoverer) removeInsertrClass(node *html.Node) {
+	classes := disc.getClasses(node)
+	var filteredClasses []string
+	for _, class := range classes {
+		if class != "insertr" {
+			filteredClasses = append(filteredClasses, class)
+		}
+	}
+	disc.setClasses(node, filteredClasses)
+}
+
 // getClasses extracts CSS classes from a node
 func (disc *Discoverer) getClasses(node *html.Node) []string {
 	for i, attr := range node.Attr {