Make post header row generic: admin cog + container_nav in shared helper

Move admin cog generation and container_nav border wrapping from
blog-specific wrapper into shared post_header_html so all services
render identical post header rows. Blog, events, cart all delegate
to the shared helper now. Cart admin pages fetch container_nav_html
via fragments. Village Hall always links to blog.

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

blog/sexp/sexp_components.py

@@ -51,36 +51,8 @@ def _blog_header_html(ctx: dict, *, oob: bool = False) -> str:
 # ---------------------------------------------------------------------------
 
 def _post_header_html(ctx: dict, *, oob: bool = False) -> str:
-    """Build the post-level header row (blog-specific: container-nav wrapping + admin cog)."""
-    overrides: dict = {}
-
-    # Blog wraps container_nav_html in border styling
-    container_nav = ctx.get("container_nav_html", "")
-    if container_nav:
-        overrides["container_nav_html"] = render("blog-container-nav",
-            container_nav_html=container_nav,
-        )
-
-    # Admin cog link
-    from quart import url_for as qurl, request
-    post = ctx.get("post") or {}
-    slug = post.get("slug", "")
-    rights = ctx.get("rights") or {}
-    has_admin = rights.get("admin") if isinstance(rights, dict) else getattr(rights, "admin", False)
-    if has_admin and slug:
-        select_colours = ctx.get("select_colours", "")
-        styles = ctx.get("styles") or {}
-        nav_btn = styles.get("nav_button", "") if isinstance(styles, dict) else getattr(styles, "nav_button", "")
-        admin_href = qurl("blog.post.admin.admin", slug=slug)
-        is_admin_page = "/admin" in request.path
-        overrides["post_admin_nav_html"] = render("nav-link",
-            href=admin_href, hx_select="#main-panel", icon="fa fa-cog",
-            aclass=f"{nav_btn} {select_colours}",
-            select_colours=select_colours, is_selected=is_admin_page,
-        )
-
-    effective_ctx = {**ctx, **overrides} if overrides else ctx
-    return _shared_post_header_html(effective_ctx, oob=oob)
+    """Build the post-level header row — delegates to shared helper."""
+    return _shared_post_header_html(ctx, oob=oob)
 
 
 # ---------------------------------------------------------------------------