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/snippets/routes.py

@@ -6,6 +6,7 @@ from sqlalchemy.orm import selectinload
 
 from shared.browser.app.authz import require_login
 from shared.browser.app.utils.htmx import is_htmx_request
+from shared.sexp.helpers import sexp_response
 from models import Snippet
 
 
@@ -46,10 +47,10 @@ def register():
         tctx["is_admin"] = is_admin
         if not is_htmx_request():
             html = await render_snippets_page(tctx)
+            return await make_response(html)
         else:
-            html = await render_snippets_oob(tctx)
-
-        return await make_response(html)
+            sexp_src = await render_snippets_oob(tctx)
+            return sexp_response(sexp_src)
 
     @bp.delete("/<int:snippet_id>/")
     @require_login
@@ -68,8 +69,7 @@ def register():
 
         snippets = await _visible_snippets(g.s)
         from sexp.sexp_components import render_snippets_list
-        html = render_snippets_list(snippets, is_admin)
-        return await make_response(html)
+        return sexp_response(render_snippets_list(snippets, is_admin))
 
     @bp.patch("/<int:snippet_id>/visibility/")
     @require_login
@@ -93,7 +93,6 @@ def register():
 
         snippets = await _visible_snippets(g.s)
         from sexp.sexp_components import render_snippets_list
-        html = render_snippets_list(snippets, True)
-        return await make_response(html)
+        return sexp_response(render_snippets_list(snippets, True))
 
     return bp