feat: decouple blog from shared_lib, add app-owned models

Phase 1-3 of decoupling:
- path_setup.py adds project root to sys.path
- Blog-owned models in blog/models/ (ghost_content, snippet, tag_group)
- Re-export shims for shared models (user, kv, magic_link, menu_item)
- All imports updated: shared.infrastructure, shared.db, shared.browser, etc.
- No more cross-app post_id FKs in calendar/market/page_config

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

bp/post/routes.py

@@ -11,16 +11,16 @@ from quart import (
 )
 from .services.post_data import post_data
 from .services.post_operations import toggle_post_like
-from models.calendars import Calendar
-from models.market_place import MarketPlace
+from events.models.calendars import Calendar
+from market.models.market_place import MarketPlace
 from sqlalchemy import select
 
-from suma_browser.app.redis_cacher import cache_page, clear_cache
+from shared.browser.app.redis_cacher import cache_page, clear_cache
 
 
 from .admin.routes import register as register_admin
-from config import config
-from suma_browser.app.utils.htmx import is_htmx_request
+from shared.config import config
+from shared.browser.app.utils.htmx import is_htmx_request
 
 def register():
   bp = Blueprint("post", __name__, url_prefix='/<slug>')
@@ -65,13 +65,13 @@ def register():
       p_data = getattr(g, "post_data", None)
       if p_data:
           from .services.entry_associations import get_associated_entries
-          from shared.internal_api import get as api_get
+          from shared.infrastructure.internal_api import get as api_get
 
           db_post_id = (g.post_data.get("post") or {}).get("id")  # <-- integer
           calendars = (
               await g.s.execute(
                   select(Calendar)
-                  .where(Calendar.post_id == db_post_id, Calendar.deleted_at.is_(None))
+                  .where(Calendar.container_type == "page", Calendar.container_id == db_post_id, Calendar.deleted_at.is_(None))
                   .order_by(Calendar.name.asc())
               )
           ).scalars().all()
@@ -79,7 +79,7 @@ def register():
           markets = (
               await g.s.execute(
                   select(MarketPlace)
-                  .where(MarketPlace.post_id == db_post_id, MarketPlace.deleted_at.is_(None))
+                  .where(MarketPlace.container_type == "page", MarketPlace.container_id == db_post_id, MarketPlace.deleted_at.is_(None))
                   .order_by(MarketPlace.name.asc())
               )
           ).scalars().all()
@@ -130,7 +130,7 @@ def register():
   @bp.post("/like/toggle/")
   @clear_cache(tag="post.post_detail", tag_scope="user")
   async def like_toggle(slug: str):
-      from utils import host_url
+      from shared.utils import host_url
 
       # Get post_id from g.post_data
       if not g.user: