Consolidate post header/menu system into shared infrastructure

Replace duplicated _post_header_html, _oob_header_html, and header-child
components across blog/events/market/errors with shared sexpr components
(~post-label, ~page-cart-badge, ~oob-header, ~header-child, ~error-content)
and shared Python helpers (post_header_html, oob_header_html,
header_child_html, error_content_html). App-specific logic (blog container-nav
wrapping, admin cog, events calendar links) preserved via thin wrappers.

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

market/sexp/sexp_components.py

@@ -14,6 +14,8 @@ from markupsafe import escape
 from shared.sexp.jinja_bridge import render, load_service_components
 from shared.sexp.helpers import (
     call_url, get_asset_url, root_header_html,
+    post_header_html as _post_header_html,
+    oob_header_html as _oob_header_html,
     search_mobile_html, search_desktop_html,
     full_page, oob_page,
 )
@@ -66,42 +68,9 @@ def _card_price_html(p: dict) -> str:
 
 
 # ---------------------------------------------------------------------------
-# Header helpers
+# Header helpers — _post_header_html and _oob_header_html imported from shared
 # ---------------------------------------------------------------------------
 
-def _post_header_html(ctx: dict, *, oob: bool = False) -> str:
-    """Build the post-level header row (feature image + title + page cart count)."""
-    post = ctx.get("post") or {}
-    slug = post.get("slug", "")
-    title = (post.get("title") or "")[:160]
-    feature_image = post.get("feature_image")
-
-    label_html = ""
-    if feature_image:
-        label_html += render("market-post-label-image", src=feature_image)
-    label_html += render("market-post-label-title", title=title)
-
-    nav_html = ""
-    page_cart_count = ctx.get("page_cart_count", 0)
-    if page_cart_count and page_cart_count > 0:
-        cart_href = call_url(ctx, "cart_url", f"/{slug}/")
-        nav_html += render("market-post-cart-badge", href=cart_href, count=str(page_cart_count))
-
-    # Container nav
-    container_nav = ctx.get("container_nav_html", "")
-    if container_nav:
-        nav_html += container_nav
-
-    link_href = call_url(ctx, "blog_url", f"/{slug}/")
-
-    return render(
-        "menu-row",
-        id="post-row", level=1,
-        link_href=link_href, link_label_html=label_html,
-        nav_html=nav_html, child_id="post-header-child", oob=oob,
-        external=True,
-    )
-
 
 def _market_header_html(ctx: dict, *, oob: bool = False) -> str:
     """Build the market-level header row (shop icon + market title + category slugs + nav)."""
@@ -1153,16 +1122,9 @@ def _market_cards_html(markets: list, page_info: dict, page: int, has_more: bool
 
 
 # ---------------------------------------------------------------------------
-# OOB header helpers
+# OOB header helpers — _oob_header_html imported from shared
 # ---------------------------------------------------------------------------
 
-def _oob_header_html(parent_id: str, child_id: str, row_html: str) -> str:
-    """Wrap a header row in OOB div with child placeholder."""
-    return render(
-        "market-oob-header",
-        parent_id=parent_id, child_id=child_id, row_html=row_html,
-    )
-
 
 # ===========================================================================
 # PUBLIC API
@@ -1258,7 +1220,7 @@ async def render_page_markets_page(ctx: dict, markets: list, has_more: bool,
     content += render("market-bottom-spacer")
 
     hdr = root_header_html(ctx)
-    hdr += render("market-header-child", inner_html=_post_header_html(ctx))
+    hdr += render("header-child", inner_html=_post_header_html(ctx))
     return full_page(ctx, header_rows_html=hdr, content_html=content)
 
 
@@ -1309,7 +1271,7 @@ async def render_market_home_page(ctx: dict) -> str:
 
     hdr = root_header_html(ctx)
     child = _post_header_html(ctx) + _market_header_html(ctx)
-    hdr += render("market-header-child", inner_html=child)
+    hdr += render("header-child", inner_html=child)
     menu = _mobile_nav_panel_html(ctx)
     return full_page(ctx, header_rows_html=hdr, content_html=content, menu_html=menu)
 
@@ -1354,7 +1316,7 @@ async def render_browse_page(ctx: dict) -> str:
 
     hdr = root_header_html(ctx)
     child = _post_header_html(ctx) + _market_header_html(ctx)
-    hdr += render("market-header-child", inner_html=child)
+    hdr += render("header-child", inner_html=child)
     menu = _mobile_nav_panel_html(ctx)
     filter_html = _mobile_filter_summary_html(ctx)
     aside_html = _desktop_filter_html(ctx)
@@ -1395,7 +1357,7 @@ async def render_product_page(ctx: dict, d: dict) -> str:
 
     hdr = root_header_html(ctx)
     child = _post_header_html(ctx) + _market_header_html(ctx) + _product_header_html(ctx, d)
-    hdr += render("market-header-child", inner_html=child)
+    hdr += render("header-child", inner_html=child)
     return full_page(ctx, header_rows_html=hdr, content_html=content, meta_html=meta)
 
 
@@ -1421,7 +1383,7 @@ async def render_product_admin_page(ctx: dict, d: dict) -> str:
     hdr = root_header_html(ctx)
     child = (_post_header_html(ctx) + _market_header_html(ctx)
              + _product_header_html(ctx, d) + _product_admin_header_html(ctx, d))
-    hdr += render("market-header-child", inner_html=child)
+    hdr += render("header-child", inner_html=child)
     return full_page(ctx, header_rows_html=hdr, content_html=content)
 
 
@@ -1459,7 +1421,7 @@ async def render_market_admin_page(ctx: dict) -> str:
 
     hdr = root_header_html(ctx)
     child = _post_header_html(ctx) + _market_header_html(ctx) + _market_admin_header_html(ctx)
-    hdr += render("market-header-child", inner_html=child)
+    hdr += render("header-child", inner_html=child)
     return full_page(ctx, header_rows_html=hdr, content_html=content)