feat(pages): add navigation label translation support

Add translation support for navigation section labels (Value Props, Features, Pricing, Blog, Gallery, Compare, etc.). Adds TemplateDefaultLabels function that returns template-specific creative names (e.g., "Systems Analysis" for value props in Architecture Deep Dive). Auto-applies defaults when enabling pages or changing templates. Includes UI fields in languages settings and translation JSON serialization. Enables full localization of section headings.

modules/pages/config.go

@@ -469,3 +469,65 @@ func TemplateDisplayNames() map[string]string {
 		"architecture-deep-dive": "Architecture Deep Dive",
 	}
 }
+
+// TemplateDefaultLabels returns the template-specific default section labels.
+// These are the creative names each template uses for its sections.
+func TemplateDefaultLabels(template string) NavigationConfig {
+	switch template {
+	case "architecture-deep-dive":
+		return NavigationConfig{
+			LabelValueProps: "Systems Analysis",
+			LabelFeatures:   "Technical Specifications",
+			LabelPricing:    "Resource Allocation",
+			LabelBlog:       "Dispatches",
+			LabelGallery:    "Visual Index",
+			LabelCompare:    "Compare",
+		}
+	case "bold-marketing":
+		return NavigationConfig{
+			LabelValueProps: "Why choose this",
+			LabelFeatures:   "Capabilities",
+			LabelPricing:    "Investment",
+			LabelBlog:       "Blog",
+			LabelGallery:    "Gallery",
+			LabelCompare:    "Compare",
+		}
+	case "minimalist-docs":
+		return NavigationConfig{
+			LabelValueProps: "Why choose this",
+			LabelFeatures:   "Capabilities",
+			LabelPricing:    "Investment",
+			LabelBlog:       "Blog",
+			LabelGallery:    "Gallery",
+			LabelCompare:    "Compare",
+		}
+	case "open-source-hero":
+		return NavigationConfig{
+			LabelValueProps: "Why choose us",
+			LabelFeatures:   "Capabilities",
+			LabelPricing:    "Pricing",
+			LabelBlog:       "Blog",
+			LabelGallery:    "Gallery",
+			LabelCompare:    "Compare",
+		}
+	case "saas-conversion":
+		return NavigationConfig{
+			LabelValueProps: "Why",
+			LabelFeatures:   "Features",
+			LabelPricing:    "Pricing",
+			LabelBlog:       "Blog",
+			LabelGallery:    "Gallery",
+			LabelCompare:    "Compare",
+		}
+	default:
+		// developer-tool, documentation-first, visual-showcase, cli-terminal
+		return NavigationConfig{
+			LabelValueProps: "Why choose us",
+			LabelFeatures:   "Capabilities",
+			LabelPricing:    "Pricing",
+			LabelBlog:       "Blog",
+			LabelGallery:    "Gallery",
+			LabelCompare:    "Compare",
+		}
+	}
+}