feat: implement Pages as Spaces Phase 1

- Add PageConfig model with feature flags (calendar, market)
- Auto-create PageConfig on Ghost page sync
- Add create_page() for Ghost /pages/ API endpoint
- Add /new-page/ route for creating pages
- Add ?type=pages blog filter with Posts|Pages tab toggle
- Add list_pages() to DBClient with PageConfig eager loading
- Add PUT /<slug>/admin/features/ route for feature toggles
- Add feature badges (calendar, market) on page cards
- Add features panel to page admin dashboard
- Update shared_lib submodule with PageConfig model

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

bp/blog/ghost/ghost_posts.py

@@ -73,6 +73,35 @@ async def create_post(
     return resp.json()["posts"][0]
 
 
+async def create_page(
+    title: str,
+    lexical_json: str,
+    status: str = "draft",
+    feature_image: str | None = None,
+    custom_excerpt: str | None = None,
+    feature_image_caption: str | None = None,
+) -> dict:
+    """Create a new page in Ghost (via /pages/ endpoint). Returns the created page dict."""
+    page_body: dict = {
+        "title": title,
+        "lexical": lexical_json,
+        "mobiledoc": None,
+        "status": status,
+    }
+    if feature_image:
+        page_body["feature_image"] = feature_image
+    if custom_excerpt:
+        page_body["custom_excerpt"] = custom_excerpt
+    if feature_image_caption is not None:
+        page_body["feature_image_caption"] = feature_image_caption
+    payload = {"pages": [page_body]}
+    url = f"{GHOST_ADMIN_API_URL}/pages/"
+    async with httpx.AsyncClient(timeout=30) as client:
+        resp = await client.post(url, json=payload, headers=_auth_header())
+        _check(resp)
+    return resp.json()["pages"][0]
+
+
 async def update_post(
     ghost_id: str,
     lexical_json: str,

bp/blog/ghost/ghost_sync.py

@@ -13,6 +13,7 @@ from sqlalchemy.orm.attributes import flag_modified  # for non-Mutable JSON colu
 from models.ghost_content import (
     Post, Author, Tag, PostAuthor, PostTag
 )
+from models.page_config import PageConfig
 
 # User-centric membership models
 from models import User
@@ -238,6 +239,15 @@ async def _upsert_post(sess: AsyncSession, gp: Dict[str, Any], author_map: Dict[
         tt = tag_map[t["id"]]
         sess.add(PostTag(post_id=obj.id, tag_id=tt.id, sort_order=idx))
 
+    # Auto-create PageConfig for pages
+    if obj.is_page:
+        existing_pc = (await sess.execute(
+            select(PageConfig).where(PageConfig.post_id == obj.id)
+        )).scalar_one_or_none()
+        if existing_pc is None:
+            sess.add(PageConfig(post_id=obj.id, features={}))
+            await sess.flush()
+
     return obj
 
 async def _ghost_find_member_by_email(email: str) -> Optional[dict]: