Add comprehensive blog demo showcasing advanced content management features

- Implement complete mushroom foraging blog with chanterelles article
- Add rich demonstration of .insertr and .insertr-add functionality
- Include comprehensive documentation for future .insertr-content vision
- Update project styling and configuration to support blog demo
- Enhance engine and API handlers for improved content management

demos/blog/insertr.yaml

@@ -0,0 +1,79 @@
+# The Forager's Journal - Blog Demo Configuration
+
+site_id: "mushroom-blog"
+
+# Discovery settings for this demo
+discovery:
+  enabled: true
+  aggressive: false
+  containers: true
+  individual: true
+
+# Content types for future blog functionality
+content_types:
+  blog_posts:
+    template: "templates/blog-post.html"
+    output_pattern: "posts/{slug}.html"
+    fields:
+      title: text
+      subtitle: text
+      content: insertr-content
+      excerpt: text
+      published_date: date
+      author: text
+      category: text
+      tags: list
+      featured_image: image
+      featured_image_alt: text
+  
+  pages:
+    template: "templates/page.html"
+    output_pattern: "{slug}.html"
+    fields:
+      title: text
+      content: insertr-content
+      meta_description: text
+
+# Example content structure for blog posts
+sample_content:
+  chanterelles_guide:
+    type: blog_posts
+    title: "Golden Treasures: A Guide to Foraging Chanterelles"
+    subtitle: "Discover the secrets to finding these golden beauties"
+    category: "Field Guide"
+    published_date: "2024-03-15"
+    author: "Elena Rodriguez"
+    tags: ["Chanterelles", "Foraging", "Identification", "Sustainable Harvesting"]
+    featured_image: "https://images.unsplash.com/photo-1518264344460-b2b8c61dbeda"
+    featured_image_alt: "Golden chanterelle mushrooms growing in forest moss"
+  
+  spring_safety:
+    type: blog_posts
+    title: "Spring Safety: Avoiding Dangerous Look-Alikes"
+    subtitle: "Essential knowledge for safe spring foraging"
+    category: "Safety"
+    published_date: "2024-03-08"
+    author: "Elena Rodriguez"
+    tags: ["Safety", "Identification", "Spring Foraging", "Look-alikes"]
+  
+  mushroom_risotto:
+    type: blog_posts
+    title: "From Forest to Table: Wild Mushroom Risotto"
+    subtitle: "Transform your harvest into an elegant dinner"
+    category: "Recipes"
+    published_date: "2024-02-28"
+    author: "Elena Rodriguez"
+    tags: ["Recipes", "Cooking", "Chanterelles", "Wild Mushrooms"]
+
+# SEO and metadata settings
+seo:
+  site_title: "The Forager's Journal"
+  site_description: "Expert guides to mushroom foraging, identification, and sustainable harvesting practices from an experienced mycophile."
+  author: "Elena Rodriguez"
+  language: "en"
+  
+# Social media settings
+social:
+  twitter_handle: "@foragers_journal"
+  facebook_page: "TheForagersJournal"
+  instagram: "@foragers.journal"