Auto-mount fragment handlers: eliminate fragment blueprint boilerplate across all 8 services

Fragment read API is now fully declarative — every handler is a defhandler
s-expression dispatched through one shared auto_mount_fragment_handlers()
function. Replaces 8 near-identical blueprint files (~35 lines each) with
a single function call per service. Events Python handlers (container-cards,
account-page) extracted to a standalone module.

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

relations/app.py

@@ -4,7 +4,7 @@ import sx.sx_components as sx_components  # noqa: F401  # ensure Hypercorn --rel
 
 from shared.infrastructure.factory import create_base_app
 
-from bp import register_actions, register_data, register_fragments
+from bp import register_actions, register_data
 from services import register_domain_services
 
 
@@ -16,7 +16,9 @@ def create_app() -> "Quart":
 
     app.register_blueprint(register_actions())
     app.register_blueprint(register_data())
-    app.register_blueprint(register_fragments())
+
+    from shared.sx.handlers import auto_mount_fragment_handlers
+    auto_mount_fragment_handlers(app, "relations")
 
     return app
 

relations/bp/__init__.py

@@ -1,3 +1,2 @@
 from .data.routes import register as register_data
 from .actions.routes import register as register_actions
-from .fragments.routes import register as register_fragments

relations/bp/fragments/routes.py

@@ -1,36 +0,0 @@
-"""Relations app fragment endpoints.
-
-Exposes sx fragments at ``/internal/fragments/<type>`` for consumption
-by other coop apps via the fragment client.
-
-All handlers are defined declaratively in .sx files under
-``relations/sx/handlers/`` and dispatched via the sx handler registry.
-"""
-
-from __future__ import annotations
-
-from quart import Blueprint, Response, request
-
-from shared.infrastructure.fragments import FRAGMENT_HEADER
-from shared.sx.handlers import get_handler, execute_handler
-
-
-def register():
-    bp = Blueprint("fragments", __name__, url_prefix="/internal/fragments")
-
-    @bp.before_request
-    async def _require_fragment_header():
-        if not request.headers.get(FRAGMENT_HEADER):
-            return Response("", status=403)
-
-    @bp.get("/<fragment_type>")
-    async def get_fragment(fragment_type: str):
-        handler_def = get_handler("relations", fragment_type)
-        if handler_def is not None:
-            result = await execute_handler(
-                handler_def, "relations", args=dict(request.args),
-            )
-            return Response(result, status=200, content_type="text/sx")
-        return Response("", status=200, content_type="text/sx")
-
-    return bp