ci: route to canonical native arcd labels [self-hosted, linux, <arch>]

Replaces non-canonical scale-set / org-prefixed labels with the
existing labels every arcd host registers with. Matches evo for
amd64 and spark for arm64. No new labels added.

.github/workflows/docker.yml

@@ -15,7 +15,7 @@ permissions:
 
 jobs:
   docker:
-    runs-on: lux-build
+    runs-on: [self-hosted, linux, amd64]
     steps:
       - uses: actions/checkout@v4
       - uses: docker/setup-qemu-action@v3

.github/workflows/docs.yml

@@ -19,7 +19,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: lux-build
+    runs-on: [self-hosted, linux, amd64]
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -56,7 +56,7 @@ jobs:
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
-    runs-on: lux-build
+    runs-on: [self-hosted, linux, amd64]
     needs: build
     steps:
       - name: Deploy to GitHub Pages