chore(reset)!: strip storefront → network-service seed (v0.9.0)

Pivot ecomm from a generic multi-tenant Shopify-alternative storefront to the
commitment-commerce + cross-maker verified referral NETWORK direction
(ecomm-content/rfcs/network_strategy.md; OHM identity/relationality super-drafts).

Phase A of the reset — clear the decks:
- Strip the storefront surfaces with no carry-forward: the storefronts domain,
  the products import/export/image HTTP spine (service/imagefetch/repo + endpoints),
  the SPA frontend, and the Playwright e2e suite.
- Keep the reusable core: /healthz + /api/auth/* (accounts); the
  catalog-normalization library (codec/dialect/models/serialize/validate/diff/hosted —
  importable, no HTTP yet); platform/* infra. Migrations untouched (append-only).
- Reduce check.sh to backend-only (import-linter + pytest); trim dev.sh and the unused
  GCS overlay env. Repoint app.json/README/CLAUDE.md; bump VERSION 0.8.0 -> 0.9.0.

check.sh green: import-linter (main > domains > platform) KEPT, pytest passing.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/tests/test_auth_endpoints.py

@@ -57,7 +57,7 @@ def test_verify_sets_cookie_and_returns_shape(fresh_db_url):
         resp = client.post("/api/auth/verify", json={"email": "merchant@example.com", "code": code})
     assert resp.status_code == 200
     data = resp.json()
-    assert data == {"account": {"email": "merchant@example.com"}, "storefront": None, "created": True}
+    assert data == {"account": {"email": "merchant@example.com"}, "created": True}
     assert "ecomm_session" in resp.cookies
 
 
@@ -115,7 +115,7 @@ def test_me_returns_account_with_session(fresh_db_url):
         client.post("/api/auth/verify", json={"email": "merchant@example.com", "code": _last_code(client)})
         resp = client.get("/api/auth/me")  # TestClient carries the cookie set by verify
     assert resp.status_code == 200
-    assert resp.json() == {"account": {"email": "merchant@example.com"}, "storefront": None}
+    assert resp.json() == {"account": {"email": "merchant@example.com"}}
 
 
 def test_puc_09_logout_clears_session(fresh_db_url):