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>

events/bp/slot/routes.py

@@ -24,6 +24,7 @@ from shared.browser.app.utils import (
     parse_cost
 )
 from shared.browser.app.utils.htmx import is_htmx_request
+from shared.sexp.helpers import sexp_response
 
 
 def register():
@@ -75,8 +76,7 @@ def register():
         if not slot:
             return await make_response("Not found", 404)
         from sexp.sexp_components import render_slot_main_panel
-        html = render_slot_main_panel(slot, g.calendar)
-        return await make_response(html)
+        return sexp_response(render_slot_main_panel(slot, g.calendar))
 
     @bp.delete("/")
     @require_admin
@@ -85,8 +85,7 @@ def register():
         await svc_delete_slot(g.s, slot_id)
         slots = await svc_list_slots(g.s, g.calendar.id)
         from sexp.sexp_components import render_slots_table
-        html = render_slots_table(slots, g.calendar)
-        return await make_response(html)
+        return sexp_response(render_slots_table(slots, g.calendar))
 
     @bp.put("/")
     @require_admin
@@ -168,8 +167,7 @@ def register():
             ), 422
 
         from sexp.sexp_components import render_slot_main_panel
-        html = render_slot_main_panel(slot, g.calendar, oob=True)
-        return await make_response(html)
+        return sexp_response(render_slot_main_panel(slot, g.calendar, oob=True))