ci: use gate-specific runner labels

Author: Jonathan Gadea Harder

.github/workflows/blueprint.yml

@@ -16,7 +16,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: self-hosted
+    runs-on: ["self-hosted", "lean", "macos"]
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -59,7 +59,7 @@ jobs:
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
-    runs-on: self-hosted
+    runs-on: ["self-hosted", "lean", "macos"]
     needs: build
     steps:
       - name: Deploy to GitHub Pages

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ on:
 
 jobs:
   build-and-verify:
-    runs-on: self-hosted
+    runs-on: ["self-hosted", "lean", "macos"]
     name: Build & Verify Formalization
     timeout-minutes: 25
     steps: