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

Phase 1-3 of decoupling:
- path_setup.py adds project root to sys.path
- Market-owned models in market/models/ (market, market_place)
- All imports updated: shared.infrastructure, shared.db, shared.browser, etc.
- MarketPlace uses container_type/container_id instead of post_id FK

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

scrape/listings.py

@@ -7,8 +7,8 @@ from urllib.parse import parse_qsl, urlencode, urljoin, urlparse, urlunparse
 
 
 from .http_client import fetch
-from suma_browser.app.bp.browse.services.slugs import product_slug_from_href
-from suma_browser.app.bp.browse.services.state import (
+from bp.browse.services.slugs import product_slug_from_href
+from bp.browse.services.state import (
     KNOWN_PRODUCT_SLUGS,
     _listing_page_cache,
     _listing_page_ttl,
@@ -16,8 +16,8 @@ from suma_browser.app.bp.browse.services.state import (
     _listing_variant_ttl,
     now,
 )
-from utils import normalize_text, soup_of
-from config import config
+from shared.utils import normalize_text, soup_of
+from shared.config import config
 
 
 def parse_total_pages_from_text(text: str) -> Optional[int]: