Wire s-expression rendering into live app — blog link-card

- Add setup_sexp_bridge() and load_shared_components() to factory.py
  so all services get s-expression support automatically
- Create shared/sexp/components.py with ~link-card component definition
  (replaces 5 per-service Jinja link_card.html templates)
- Replace blog's link-card fragment handler to use sexp() instead of
  render_template() — first real s-expression rendered page content

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

blog/bp/fragments/routes.py

@@ -10,6 +10,7 @@ from quart import Blueprint, Response, g, render_template, request
 
 from shared.infrastructure.fragments import FRAGMENT_HEADER
 from shared.services.navigation import get_navigation_tree
+from shared.sexp.jinja_bridge import sexp
 
 
 def register():
@@ -57,7 +58,21 @@ def register():
 
     _handlers["nav-tree"] = _nav_tree_handler
 
-    # --- link-card fragment ---
+    # --- link-card fragment (s-expression rendered) ---
+    def _render_blog_link_card(post, link: str) -> str:
+        """Render a blog link-card via the ~link-card s-expression component."""
+        published = post.published_at.strftime("%d %b %Y") if post.published_at else None
+        return sexp(
+            '(~link-card :link link :title title :image image'
+            ' :icon "fas fa-file-alt" :subtitle excerpt'
+            ' :detail published :data-app "blog")',
+            link=link,
+            title=post.title,
+            image=post.feature_image,
+            excerpt=post.custom_excerpt or post.excerpt,
+            published=published,
+        )
+
     async def _link_card_handler():
         from shared.services.registry import services
         from shared.infrastructure.urls import blog_url
@@ -73,14 +88,7 @@ def register():
                 parts.append(f"<!-- fragment:{s} -->")
                 post = await services.blog.get_post_by_slug(g.s, s)
                 if post:
-                    parts.append(await render_template(
-                        "fragments/link_card.html",
-                        title=post.title,
-                        feature_image=post.feature_image,
-                        excerpt=post.custom_excerpt or post.excerpt,
-                        published_at=post.published_at,
-                        link=blog_url(f"/{post.slug}"),
-                    ))
+                    parts.append(_render_blog_link_card(post, blog_url(f"/{post.slug}")))
             return "\n".join(parts)
 
         # Single mode
@@ -89,14 +97,7 @@ def register():
         post = await services.blog.get_post_by_slug(g.s, slug)
         if not post:
             return ""
-        return await render_template(
-            "fragments/link_card.html",
-            title=post.title,
-            feature_image=post.feature_image,
-            excerpt=post.custom_excerpt or post.excerpt,
-            published_at=post.published_at,
-            link=blog_url(f"/{post.slug}"),
-        )
+        return _render_blog_link_card(post, blog_url(f"/{post.slug}"))
 
     _handlers["link-card"] = _link_card_handler