Fix page editing: use Ghost /pages/ API for pages, not /posts/

Ghost has separate /posts/ and /pages/ endpoints. All admin functions
(get_post_for_edit, update_post, update_post_settings, sync) were
hardcoded to /posts/, causing 404s when editing pages. Now checks
is_page from post_data and uses the correct endpoint.

Also uses sync_single_page (not sync_single_post) after page saves
to prevent IntegrityError from mismatched fetch/upsert paths.

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

bp/post/admin/routes.py

@@ -367,7 +367,8 @@ def register():
     from ...blog.ghost.ghost_posts import get_post_for_edit
 
     ghost_id = g.post_data["post"]["ghost_id"]
-    ghost_post = await get_post_for_edit(ghost_id)
+    is_page = bool(g.post_data["post"].get("is_page"))
+    ghost_post = await get_post_for_edit(ghost_id, is_page=is_page)
     save_success = request.args.get("saved") == "1"
 
     if not is_htmx_request():
@@ -389,10 +390,11 @@ def register():
   @require_post_author
   async def settings_save(slug: str):
     from ...blog.ghost.ghost_posts import update_post_settings
-    from ...blog.ghost.ghost_sync import sync_single_post
+    from ...blog.ghost.ghost_sync import sync_single_post, sync_single_page
     from shared.browser.app.redis_cacher import invalidate_tag_cache
 
     ghost_id = g.post_data["post"]["ghost_id"]
+    is_page = bool(g.post_data["post"].get("is_page"))
     form = await request.form
 
     updated_at = form.get("updated_at", "")
@@ -436,11 +438,15 @@ def register():
     await update_post_settings(
         ghost_id=ghost_id,
         updated_at=updated_at,
+        is_page=is_page,
         **kwargs,
     )
 
     # Sync to local DB
-    await sync_single_post(g.s, ghost_id)
+    if is_page:
+        await sync_single_page(g.s, ghost_id)
+    else:
+        await sync_single_post(g.s, ghost_id)
     await g.s.flush()
 
     # Clear caches
@@ -457,7 +463,8 @@ def register():
     from sqlalchemy import select as sa_select
 
     ghost_id = g.post_data["post"]["ghost_id"]
-    ghost_post = await get_post_for_edit(ghost_id)
+    is_page = bool(g.post_data["post"].get("is_page"))
+    ghost_post = await get_post_for_edit(ghost_id, is_page=is_page)
     save_success = request.args.get("saved") == "1"
 
     newsletters = (await g.s.execute(
@@ -487,10 +494,11 @@ def register():
     import json
     from ...blog.ghost.ghost_posts import update_post
     from ...blog.ghost.lexical_validator import validate_lexical
-    from ...blog.ghost.ghost_sync import sync_single_post
+    from ...blog.ghost.ghost_sync import sync_single_post, sync_single_page
     from shared.browser.app.redis_cacher import invalidate_tag_cache
 
     ghost_id = g.post_data["post"]["ghost_id"]
+    is_page = bool(g.post_data["post"].get("is_page"))
     form = await request.form
     title = form.get("title", "").strip()
     lexical_raw = form.get("lexical", "")
@@ -507,7 +515,7 @@ def register():
       lexical_doc = json.loads(lexical_raw)
     except (json.JSONDecodeError, TypeError):
       from ...blog.ghost.ghost_posts import get_post_for_edit
-      ghost_post = await get_post_for_edit(ghost_id)
+      ghost_post = await get_post_for_edit(ghost_id, is_page=is_page)
       html = await render_template(
           "_types/post_edit/index.html",
           ghost_post=ghost_post,
@@ -518,7 +526,7 @@ def register():
     ok, reason = validate_lexical(lexical_doc)
     if not ok:
       from ...blog.ghost.ghost_posts import get_post_for_edit
-      ghost_post = await get_post_for_edit(ghost_id)
+      ghost_post = await get_post_for_edit(ghost_id, is_page=is_page)
       html = await render_template(
           "_types/post_edit/index.html",
           ghost_post=ghost_post,
@@ -535,6 +543,7 @@ def register():
         feature_image=feature_image,
         custom_excerpt=custom_excerpt,
         feature_image_caption=feature_image_caption,
+        is_page=is_page,
     )
 
     # Publish workflow
@@ -565,11 +574,15 @@ def register():
           title=None,
           updated_at=ghost_post["updated_at"],
           status=status,
+          is_page=is_page,
           **email_kwargs,
       )
 
     # Sync to local DB
-    await sync_single_post(g.s, ghost_id)
+    if is_page:
+        await sync_single_page(g.s, ghost_id)
+    else:
+        await sync_single_post(g.s, ghost_id)
     await g.s.flush()
 
     # Handle publish_requested flag on the local post