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>

federation/app.py

@@ -12,7 +12,6 @@ from shared.services.registry import services
 from bp import (
     register_identity_bp,
     register_social_bp,
-    register_fragments,
 )
 
 
@@ -99,7 +98,8 @@ def create_app() -> "Quart":
     from shared.sx.pages import auto_mount_pages
     auto_mount_pages(app, "federation")
 
-    app.register_blueprint(register_fragments())
+    from shared.sx.handlers import auto_mount_fragment_handlers
+    auto_mount_fragment_handlers(app, "federation")
 
     # --- home page ---
     @app.get("/")

federation/bp/__init__.py

@@ -1,3 +1,2 @@
 from .identity.routes import register as register_identity_bp
 from .social.routes import register as register_social_bp
-from .fragments import register_fragments

federation/bp/fragments/__init__.py

@@ -1 +0,0 @@
-from .routes import register as register_fragments

federation/bp/fragments/routes.py

@@ -1,36 +0,0 @@
-"""Federation 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
-``federation/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("federation", fragment_type)
-        if handler_def is not None:
-            result = await execute_handler(
-                handler_def, "federation", args=dict(request.args),
-            )
-            return Response(result, status=200, content_type="text/sx")
-        return Response("", status=200, content_type="text/sx")
-
-    return bp