Migrate all apps to defpage declarative page routes

Replace Python GET page handlers with declarative defpage definitions in .sx
files across all 8 apps (sx docs, orders, account, market, cart, federation,
events, blog). Each app now has sxc/pages/ with setup functions, layout
registrations, page helpers, and .sx defpage declarations.

Core infrastructure: add g I/O primitive, PageDef support for auth/layout/
data/content/filter/aside/menu slots, post_author auth level, and custom
layout registration. Remove ~1400 lines of render_*_page/render_*_oob
boilerplate. Update all endpoint references in routes, sx_components, and
templates to defpage_* naming.

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

federation/sxc/pages/__init__.py

@@ -0,0 +1,109 @@
+"""Federation defpage setup — registers layouts, page helpers, and loads .sx pages."""
+from __future__ import annotations
+
+from typing import Any
+
+
+def setup_federation_pages() -> None:
+    """Register federation-specific layouts, page helpers, and load page definitions."""
+    _register_federation_layouts()
+    _register_federation_helpers()
+    _load_federation_page_files()
+
+
+def _load_federation_page_files() -> None:
+    import os
+    from shared.sx.pages import load_page_dir
+    load_page_dir(os.path.dirname(__file__), "federation")
+
+
+# ---------------------------------------------------------------------------
+# Layouts
+# ---------------------------------------------------------------------------
+
+def _register_federation_layouts() -> None:
+    from shared.sx.layouts import register_custom_layout
+    register_custom_layout("social", _social_full, _social_oob)
+
+
+def _social_full(ctx: dict, **kw: Any) -> str:
+    from shared.sx.helpers import root_header_sx, header_child_sx
+    from sx.sx_components import _social_header_sx
+
+    actor = ctx.get("actor")
+    root_hdr = root_header_sx(ctx)
+    social_hdr = _social_header_sx(actor)
+    child = header_child_sx(social_hdr)
+    return "(<> " + root_hdr + " " + child + ")"
+
+
+def _social_oob(ctx: dict, **kw: Any) -> str:
+    from shared.sx.helpers import root_header_sx, sx_call, SxExpr
+    from sx.sx_components import _social_header_sx
+
+    actor = ctx.get("actor")
+    social_hdr = _social_header_sx(actor)
+    child_oob = sx_call("oob-header-sx",
+                         parent_id="root-header-child",
+                         row=SxExpr(social_hdr))
+    root_hdr_oob = root_header_sx(ctx, oob=True)
+    return "(<> " + child_oob + " " + root_hdr_oob + ")"
+
+
+# ---------------------------------------------------------------------------
+# Page helpers
+# ---------------------------------------------------------------------------
+
+def _register_federation_helpers() -> None:
+    from shared.sx.pages import register_page_helpers
+
+    register_page_helpers("federation", {
+        "home-timeline-content": _h_home_timeline_content,
+        "public-timeline-content": _h_public_timeline_content,
+        "compose-content": _h_compose_content,
+        "search-content": _h_search_content,
+        "following-content": _h_following_content,
+        "followers-content": _h_followers_content,
+        "actor-timeline-content": _h_actor_timeline_content,
+        "notifications-content": _h_notifications_content,
+    })
+
+
+def _h_home_timeline_content():
+    from quart import g
+    return getattr(g, "home_timeline_content", "")
+
+
+def _h_public_timeline_content():
+    from quart import g
+    return getattr(g, "public_timeline_content", "")
+
+
+def _h_compose_content():
+    from quart import g
+    return getattr(g, "compose_content", "")
+
+
+def _h_search_content():
+    from quart import g
+    return getattr(g, "search_content", "")
+
+
+def _h_following_content():
+    from quart import g
+    return getattr(g, "following_content", "")
+
+
+def _h_followers_content():
+    from quart import g
+    return getattr(g, "followers_content", "")
+
+
+def _h_actor_timeline_content():
+    from quart import g
+    return getattr(g, "actor_timeline_content", "")
+
+
+def _h_notifications_content():
+    from quart import g
+    return getattr(g, "notifications_content", "")

federation/sxc/pages/social.sx

@@ -0,0 +1,49 @@
+;; Federation social pages
+
+(defpage home-timeline
+  :path "/"
+  :auth :login
+  :layout :social
+  :content (home-timeline-content))
+
+(defpage public-timeline
+  :path "/public"
+  :auth :public
+  :layout :social
+  :content (public-timeline-content))
+
+(defpage compose-form
+  :path "/compose"
+  :auth :login
+  :layout :social
+  :content (compose-content))
+
+(defpage search
+  :path "/search"
+  :auth :public
+  :layout :social
+  :content (search-content))
+
+(defpage following-list
+  :path "/following"
+  :auth :login
+  :layout :social
+  :content (following-content))
+
+(defpage followers-list
+  :path "/followers"
+  :auth :login
+  :layout :social
+  :content (followers-content))
+
+(defpage actor-timeline
+  :path "/actor/<int:id>"
+  :auth :public
+  :layout :social
+  :content (actor-timeline-content))
+
+(defpage notifications
+  :path "/notifications"
+  :auth :login
+  :layout :social
+  :content (notifications-content))