Decouple blog UI via widget registry

Replace explicit calendar/market service calls in post routes, auth
routes, and listing cards with widget-driven iteration. Zero cross-domain
imports remain in blog bp layer.

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

bp/post/routes.py

@@ -8,10 +8,12 @@ from quart import (
     Blueprint,
     abort,
     url_for,
+    request,
 )
 from .services.post_data import post_data
 from .services.post_operations import toggle_post_like
 from shared.services.registry import services
+from shared.services.widget_registry import widgets
 
 from shared.browser.app.redis_cacher import cache_page, clear_cache
 
@@ -62,25 +64,29 @@ def register():
   async def context():
       p_data = getattr(g, "post_data", None)
       if p_data:
-          from .services.entry_associations import get_associated_entries
           from shared.infrastructure.cart_identity import current_cart_identity
 
-          db_post_id = (g.post_data.get("post") or {}).get("id")  # <-- integer
-          calendars = await services.calendar.calendars_for_container(g.s, "page", db_post_id)
-          markets = await services.market.marketplaces_for_container(g.s, "page", db_post_id)
+          db_post_id = (g.post_data.get("post") or {}).get("id")
+          post_slug = (g.post_data.get("post") or {}).get("slug", "")
 
-          # Fetch associated entries for nav display
-          associated_entries = await get_associated_entries(g.s, db_post_id)
+          # Widget-driven container nav — only include widgets with data
+          container_nav_loaded = []
+          for w in widgets.container_nav:
+              wctx = await w.context_fn(
+                  g.s, container_type="page", container_id=db_post_id,
+                  post_slug=post_slug,
+              )
+              # Include widget if it has any list data
+              if any(v for v in wctx.values() if isinstance(v, list) and v):
+                  container_nav_loaded.append({"widget": w, "ctx": wctx})
 
           ctx = {
               **p_data,
               "base_title": f"{config()['title']} {p_data['post']['title']}",
-              "calendars": calendars,
-              "markets": markets,
-              "associated_entries": associated_entries,
+              "container_nav_widgets": container_nav_loaded,
           }
 
-          # Page cart badge via service (replaces cross-app HTTP API)
+          # Page cart badge via service
           post_dict = p_data.get("post") or {}
           if post_dict.get("is_page"):
               ident = current_cart_identity()
@@ -143,24 +149,23 @@ def register():
       )
       return html
 
-  @bp.get("/entries/")
-  async def get_entries(slug: str):
-      """Get paginated associated entries for infinite scroll in nav"""
-      from .services.entry_associations import get_associated_entries
-      from quart import request
-
+  @bp.get("/w/<widget_domain>/")
+  async def widget_paginate(slug: str, widget_domain: str):
+      """Generic paginated widget endpoint for infinite scroll."""
       page = int(request.args.get("page", 1))
       post_id = g.post_data["post"]["id"]
 
-      result = await get_associated_entries(g.s, post_id, page=page, per_page=10)
-
-      html = await render_template(
-          "_types/post/_entry_items.html",
-          entries=result["entries"],
-          page=result["page"],
-          has_more=result["has_more"],
-      )
-      return await make_response(html)
+      for w in widgets.container_nav:
+          if w.domain == widget_domain:
+              ctx = await w.context_fn(
+                  g.s, container_type="page", container_id=post_id,
+                  post_slug=slug, page=page,
+              )
+              html = await render_template(
+                  w.template, ctx=ctx, post=g.post_data["post"],
+              )
+              return await make_response(html)
+      abort(404)
 
   return bp