Rename coop to blog in app code and config

- App name: "coop" → "blog"
- coop_context() → blog_context()
- coop_url → blog_url imports
- app_url("coop") → app_url("blog")
- Config keys: coop_root/coop_title → market_root/market_title
- Sync shared submodule

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

bp/auth/services/login_redirect.py

@@ -1,7 +1,7 @@
 from urllib.parse import urlparse
 from quart import session
 
-from shared.infrastructure.urls import coop_url
+from shared.infrastructure.urls import blog_url
 
 
 LOGIN_REDIRECT_SESSION_KEY = "login_redirect_to"
@@ -32,7 +32,7 @@ def store_login_redirect_target() -> None:
 def pop_login_redirect_target() -> str:
     path = session.pop(LOGIN_REDIRECT_SESSION_KEY, None)
     if not path or not isinstance(path, str):
-        return coop_url("/auth/")
+        return blog_url("/auth/")
 
     # Absolute URL: return as-is (cross-app redirect)
     if path.startswith("http://") or path.startswith("https://"):
@@ -40,6 +40,6 @@ def pop_login_redirect_target() -> str:
 
     # Relative path: must start with / and not //
     if path.startswith("/") and not path.startswith("//"):
-        return coop_url(path)
+        return blog_url(path)
 
-    return coop_url("/auth/")
+    return blog_url("/auth/")