feat(auth): integrate authentication with installation lifecycle

deploy/compose.server.yaml

@@ -1,7 +1,6 @@
 services:
   core:
     environment:
-      AUTH_MODE: upstream
       THOTH_PUBLIC_EXPOSURE: "true"
       THT_DATA_ROOT: /data
       THT_WORKSPACE_INSTALLATION_ID: server
@@ -11,6 +10,10 @@ services:
       - type: bind
         source: ${THT_DATA_ROOT:?set THT_DATA_ROOT}
         target: /data
+      - type: bind
+        source: ${THT_AUTH_CONFIG_ROOT:?set THT_AUTH_CONFIG_ROOT}
+        target: /run/thothii-auth
+        read_only: true
       - type: bind
         source: ${THT_PI_STATE_ROOT:?set THT_PI_STATE_ROOT}
         target: /home/thoth/.pi
@@ -30,6 +33,8 @@ services:
         source: ${THT_WORKSPACE_REGISTRY_ROOT:?set THT_WORKSPACE_REGISTRY_ROOT}
         target: /data/workspace-registry
     restart: unless-stopped
+    # Deprecated migration adapter: only use this when no auth.yaml is mounted yet.
+    # AUTH_MODE: upstream
 
   frontend:
     ports: