Send all responses as sexp wire format with client-side rendering

- Server sends sexp source text, client (sexp.js) renders everything
- SexpExpr marker class for nested sexp composition in serialize()
- sexp_page() HTML shell with data-mount="body" for full page loads
- sexp_response() returns text/sexp for OOB/partial responses
- ~app-body layout component replaces ~app-layout (no raw!)
- ~rich-text is the only component using raw! (for CMS HTML content)
- Fragment endpoints return text/sexp, auto-wrapped in SexpExpr
- All _*_html() helpers converted to _*_sexp() returning sexp source
- Head auto-hoist: sexp.js moves meta/title/link/script[ld+json]
  from rendered body to document.head automatically
- Unknown components render warning box instead of crashing page
- Component kwargs preserve AST for lazy rendering (fixes <> in kwargs)
- Fix unterminated paren in events/sexp/tickets.sexpr

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

blog/bp/fragments/routes.py

@@ -1,6 +1,6 @@
 """Blog app fragment endpoints.
 
-Exposes HTML fragments at ``/internal/fragments/<type>`` for consumption
+Exposes sexp fragments at ``/internal/fragments/<type>`` for consumption
 by other coop apps via the fragment client.
 """
 
@@ -10,13 +10,11 @@ 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():
     bp = Blueprint("fragments", __name__, url_prefix="/internal/fragments")
 
-    # Registry of fragment handlers: type -> async callable returning HTML str
     _handlers: dict[str, object] = {}
 
     @bp.before_request
@@ -28,18 +26,19 @@ def register():
     async def get_fragment(fragment_type: str):
         handler = _handlers.get(fragment_type)
         if handler is None:
-            return Response("", status=200, content_type="text/html")
-        html = await handler()
-        return Response(html, status=200, content_type="text/html")
+            return Response("", status=200, content_type="text/sexp")
+        result = await handler()
+        # nav-tree still returns HTML (Jinja template) for now
+        ct = "text/html" if fragment_type == "nav-tree" else "text/sexp"
+        return Response(result, status=200, content_type=ct)
 
-    # --- nav-tree fragment ---
+    # --- nav-tree fragment (still Jinja for now — complex template) ---
     async def _nav_tree_handler():
         app_name = request.args.get("app_name", "")
         path = request.args.get("path", "/")
         first_seg = path.strip("/").split("/")[0]
         menu_items = list(await get_navigation_tree(g.s))
 
-        # Append Art-DAG as a synthetic nav entry (not a DB MenuNode)
         class _NavItem:
             __slots__ = ("slug", "label", "feature_image")
             def __init__(self, slug, label, feature_image=None):
@@ -58,20 +57,18 @@ def register():
 
     _handlers["nav-tree"] = _nav_tree_handler
 
-    # --- 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."""
+    # --- link-card fragment — returns sexp source ---
+    def _blog_link_card_sexp(post, link: str) -> str:
+        from shared.sexp.helpers import sexp_call
         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,
-        )
+        return sexp_call("link-card",
+                         link=link,
+                         title=post.title,
+                         image=post.feature_image,
+                         icon="fas fa-file-alt",
+                         subtitle=post.custom_excerpt or post.excerpt,
+                         detail=published,
+                         data_app="blog")
 
     async def _link_card_handler():
         from shared.services.registry import services
@@ -88,7 +85,7 @@ def register():
                 parts.append(f"<!-- fragment:{s} -->")
                 post = await services.blog.get_post_by_slug(g.s, s)
                 if post:
-                    parts.append(_render_blog_link_card(post, blog_url(f"/{post.slug}")))
+                    parts.append(_blog_link_card_sexp(post, blog_url(f"/{post.slug}")))
             return "\n".join(parts)
 
         # Single mode
@@ -97,11 +94,10 @@ def register():
         post = await services.blog.get_post_by_slug(g.s, slug)
         if not post:
             return ""
-        return _render_blog_link_card(post, blog_url(f"/{post.slug}"))
+        return _blog_link_card_sexp(post, blog_url(f"/{post.slug}"))
 
     _handlers["link-card"] = _link_card_handler
 
-    # Store handlers dict on blueprint so app code can register handlers
     bp._fragment_handlers = _handlers
 
     return bp