feat(scaffolder): Create scaffolder mcp action to list all installed template actions (#32765)

* add scaffolder mcp action to list all installed template actions

Signed-off-by: Stephanie <yangcao@redhat.com>

* add changeset

Signed-off-by: Stephanie <yangcao@redhat.com>

* resolve review comments

Signed-off-by: Stephanie <yangcao@redhat.com>

* cleanup code

Signed-off-by: Stephanie <yangcao@redhat.com>

* resolve pr review comments

Signed-off-by: Stephanie <yangcao@redhat.com>

* remove actionService param in options, as templateActionsRegistry has already been passed in

Signed-off-by: Stephanie <yangcao@redhat.com>

* remove unnecessary required param check

Signed-off-by: Stephanie <yangcao@redhat.com>

* type the mcp action output better

Signed-off-by: Stephanie <yangcao@redhat.com>

* use scaffolderService instead

Signed-off-by: Stephanie <yangcao@redhat.com>

* revert templateActionRegistry rename, keep actionRegistry as-is

Signed-off-by: benjdlambert <ben@blam.sh>

* clean up list-scaffolder-actions: fix tests, changeset, and description

Signed-off-by: benjdlambert <ben@blam.sh>

---------

Signed-off-by: Stephanie <yangcao@redhat.com>
Signed-off-by: benjdlambert <ben@blam.sh>
Co-authored-by: benjdlambert <ben@blam.sh>

app-config.yaml

@@ -68,6 +68,7 @@ backend:
   actions:
     pluginSources:
       - catalog
+      - scaffolder
 # See README.md in the proxy-backend plugin for information on the configuration format
 proxy:
   endpoints: