Registry: UI Logout function does not redirect correctly when using `routingMode = path`

[snorlaX-sleeps]

Related issue: #390
PR adding path based routing to the Helm Chart: #395

Issue

When the routing mode is set to path the registry logout function uses the host header to determine the redirect_uri that is passed to both the auth-server and keycloak.
This should be updated to include the root_path when it is set
Registry Logout function using the host header: https://github.com/agentic-community/mcp-gateway-registry/blob/main/registry/auth/routes.py#L238
Both the auth-server and keycloak use the redirect_uri from the registry.

Example logs from logout attempt

Removing the host but leaving the root_path in the logs

Registry

registry-7c5bc5b86c-vzd4g registry 2026-02-17 19:56:46,558,p114,{routes.py:223},INFO,User was authenticated via OAuth2 provider: keycloak
registry-7c5bc5b86c-vzd4g registry 2026-02-17 19:56:46,558,p114,{routes.py:254},INFO,Redirecting to keycloak logout: https://<host>/auth-server/oauth2/logout/keycloak?redirect_uri=https://<host>/logout
registry-7c5bc5b86c-vzd4g registry 2026-02-17 19:56:46,558,p114,{routes.py:258},INFO,User logged out.

Auth Server

auth-server-66f6c4f5c7-z7gms auth-server 2026-02-17 19:09:56,496,p1,{server.py:2781},INFO,Redirecting to keycloak logout: https://<host>/keycloak/realms/mcp-gateway/protocol/openid-connect/logout?client_id=mcp-gateway-web&post_logout_redirect_uri=https%3A%2F%2F<host>%2Flogout
auth-server-66f6c4f5c7-z7gms auth-server INFO:     10.0.38.254:47363 - "GET /auth-server/oauth2/logout/keycloak?redirect_uri=https://<host>/logout HTTP/1.1" 302 Found

KeyCloak

mcp-gateway-registry-keycloak-0 keycloak 2026-02-17 19:56:46,802 WARN  [org.keycloak.events] (executor-thread-22) type="LOGOUT_ERROR", realmId="fe28af42-fd6c-4aee-921d-8d893a7666b9", realmName="mcp-gateway", clientId="mcp-gateway-web", userId="null", ipAddress="ip", error="invalid_redirect_uri", redirect_uri="https://<host>/logout"

This is not the same issue as #490 but they are both happening when trying to change users