app-catalog: Add artifacthub-pkg.yml metadata

Changes:
- Add artifacthub-pkg.yml for App Catalog plugin
- Rename package to @headlamp-k8s/app-catalog
- Regenerate package-lock.json after rename

Signed-off-by: Aadhil Ahamed <aadhil2k4@gmail.com>

Author: aadhil2k4

app-catalog/artifacthub-pkg.yml

@@ -0,0 +1,10 @@
+version: 0.8.0
+name: headlamp_app-catalog
+displayName: app-catalog
+createdAt: "2025-12-15T16:23:00Z"
+description: An app catalog for Headlamp.
+annotations:
+  headlamp/plugin/archive-url: https://github.com/headlamp-k8s/plugins/releases/download/app-catalog-0.8.0/headlamp-k8s-app-catalog-0.8.0.tar.gz
+  headlamp/plugin/archive-checksum: "SHA256:2295f944de00dc08e78c45d8989580ae737de3c686597fcd6afa93a4588837b4"
+  headlamp/plugin/version-compat: ">=0.22"
+  headlamp/plugin/distro-compat: in-cluster,web,docker-desktop,desktop