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>

shared/infrastructure/factory.py

@@ -28,6 +28,8 @@ from shared.browser.app.errors import errors
 
 from .jinja_setup import setup_jinja
 from .user_loader import load_current_user
+from shared.sexp.jinja_bridge import setup_sexp_bridge
+from shared.sexp.components import load_shared_components
 
 
 # Async init of config (runs once at import)
@@ -104,6 +106,8 @@ def create_base_app(
     register_db(app)
     register_redis(app)
     setup_jinja(app)
+    setup_sexp_bridge(app)
+    load_shared_components()
     errors(app)
 
     # Auto-register OAuth client blueprint for non-account apps

shared/sexp/components.py

@@ -0,0 +1,51 @@
+"""
+Shared s-expression component definitions.
+
+Loaded at app startup via ``load_shared_components()``.  Each component
+replaces a per-service Jinja fragment template with a single reusable
+s-expression definition.
+"""
+
+from __future__ import annotations
+
+from .jinja_bridge import register_components
+
+
+def load_shared_components() -> None:
+    """Register all shared s-expression components."""
+    register_components(_LINK_CARD)
+
+
+# ---------------------------------------------------------------------------
+# ~link-card
+# ---------------------------------------------------------------------------
+# Replaces: blog/templates/fragments/link_card.html
+#           market/templates/fragments/link_card.html
+#           events/templates/fragments/link_card.html
+#           federation/templates/fragments/link_card.html
+#           artdag/l1/app/templates/fragments/link_card.html
+#
+# Usage:
+#   sexp('(~link-card :link "/post/apple/" :title "Apple" :image "/img/a.jpg")')
+#   sexp('(~link-card :link url :title title :icon "fas fa-file-alt")', **ctx)
+# ---------------------------------------------------------------------------
+
+_LINK_CARD = '''
+(defcomp ~link-card (&key link title image icon subtitle detail data-app)
+  (a :href link
+     :class "block rounded border border-stone-200 bg-white hover:bg-stone-50 transition-colors no-underline"
+     :data-fragment "link-card"
+     :data-app data-app
+     :data-hx-disable true
+    (div :class "flex flex-row items-start gap-3 p-3"
+      (if image
+        (img :src image :alt "" :class "flex-shrink-0 w-16 h-16 rounded object-cover")
+        (div :class "flex-shrink-0 w-16 h-16 rounded bg-stone-100 flex items-center justify-center text-stone-400"
+          (i :class icon)))
+      (div :class "flex-1 min-w-0"
+        (div :class "font-medium text-stone-900 text-sm clamp-2" title)
+        (when subtitle
+          (div :class "text-xs text-stone-500 mt-0.5" subtitle))
+        (when detail
+          (div :class "text-xs text-stone-400 mt-1" detail))))))
+'''