fix: Append redirect stage to TOTP/WebAuthn self-service setup flows

2FA is intentionally optional (not_configured_action=skip on the login
flow's validate stage). Users who opt in use the built-in single-stage
default-authenticator-totp-setup / -webauthn-setup flows directly, since
/if/user/ is blocked for type=external Matrix accounts. Both flows had
nothing after the setup stage, so completing enrollment fell back to
that same blocked dashboard. Appended the shared redirect stage.

apps/authentik/authentik-blueprints.yaml

@@ -177,3 +177,32 @@ data:
           name: default-authentication-identification
         attrs:
           recovery_flow: !KeyOf matrix_recovery_flow
+  matrix-mfa-setup-redirect.yaml: |
+    # yaml-language-server: $schema=https://goauthentik.io/blueprints/schema.json
+    version: 1
+    metadata:
+      name: matrix-mfa-setup-redirect
+      labels:
+        blueprints.goauthentik.io/instantiate: "true"
+    entries:
+      # 2FA is optional (default-authentication-mfa-validation has
+      # not_configured_action=skip - login never blocks on missing MFA).
+      # Users who want to opt in use these built-in single-stage setup flows
+      # directly (unreachable via /if/user/, which is blocked for type=external
+      # Matrix accounts). Without a stage after the setup itself, completion
+      # fell back to the same blocked /if/user/ dashboard - append our redirect.
+      - model: authentik_flows.flowstagebinding
+        state: present
+        identifiers:
+          target: !Find [authentik_flows.flow, [slug, default-authenticator-totp-setup]]
+          order: 10
+        attrs:
+          stage: !Find [authentik_stages_redirect.redirectstage, [name, matrix-invitation-redirect]]
+
+      - model: authentik_flows.flowstagebinding
+        state: present
+        identifiers:
+          target: !Find [authentik_flows.flow, [slug, default-authenticator-webauthn-setup]]
+          order: 10
+        attrs:
+          stage: !Find [authentik_stages_redirect.redirectstage, [name, matrix-invitation-redirect]]