Fix problematic Hookshot redirect for /hookshot/widgetapi/v1/static

Hookshot wants a trailing slash for this route.

If we let Hookshot redirect, it goes to `/widgetapi/v1/static/`,
instead of `/hookshot/widgetapi/v1/static/`, so we take this matter into our
own hands.

roles/custom/matrix-bridge-hookshot/defaults/main.yml

@@ -203,7 +203,7 @@ matrix_hookshot_widgets_disallowedIpRanges: ''   # noqa var-naming
 matrix_hookshot_widgets_internal: "/widgetapi"
 matrix_hookshot_widgets_hostname: "{{ matrix_hookshot_public_hostname }}"
 matrix_hookshot_widgets_endpoint: "{{ matrix_hookshot_public_endpoint }}{{ matrix_hookshot_widgets_internal }}"
-matrix_hookshot_widgets_publicUrl: "{{ matrix_hookshot_urlprefix }}{{ matrix_hookshot_widgets_endpoint }}/v1/static"   # noqa var-naming
+matrix_hookshot_widgets_publicUrl: "{{ matrix_hookshot_urlprefix }}{{ matrix_hookshot_widgets_endpoint }}/v1/static/"   # noqa var-naming
 matrix_hookshot_widgets_branding_widgetTitle: "Hookshot Configuration"   # noqa var-naming
 
 

roles/custom/matrix-bridge-hookshot/templates/labels.j2

@@ -83,10 +83,15 @@ traefik.http.routers.matrix-hookshot-appservice.tls.certResolver={{ matrix_hooks
 #                                                          #
 ############################################################
 
+# Redirect `{PREFIX}/widgetapi/v1/static` to `{PREFIX}/widgetapi/v1/static/`.
+# Hookshot does it too, but does not obey the prefix, which leads people elsewhere.
+traefik.http.middlewares.matrix-hookshot-widgets-slashless-redirect.redirectregex.regex=({{ matrix_hookshot_widgets_endpoint | quote }}/v1/static)$
+traefik.http.middlewares.matrix-hookshot-widgets-slashless-redirect.redirectregex.replacement=${1}/
+
 traefik.http.middlewares.matrix-hookshot-widgets-strip-prefix.stripprefix.prefixes={{ matrix_hookshot_public_endpoint }}
 
 traefik.http.routers.matrix-hookshot-widgets.rule={{ matrix_hookshot_container_labels_widgets_traefik_rule }}
-traefik.http.routers.matrix-hookshot-widgets.middlewares=matrix-hookshot-widgets-strip-prefix
+traefik.http.routers.matrix-hookshot-widgets.middlewares=matrix-hookshot-widgets-slashless-redirect,matrix-hookshot-widgets-strip-prefix
 
 {% if matrix_hookshot_container_labels_widgets_traefik_priority | int > 0 %}
 traefik.http.routers.matrix-hookshot-widgets.priority={{ matrix_hookshot_container_labels_widgets_traefik_priority }}