ci: pin ubuntu runners to ubuntu-26.04 instead of ubuntu-latest

.github/workflows/build-docs.yml

@@ -23,7 +23,8 @@ jobs:
   # artifact might actually be deployed (see the 'deploy' job below).
   build:
     if: ${{ github.event_name == 'release' || github.event_name == 'workflow_dispatch' }}
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7
@@ -53,7 +54,8 @@ jobs:
   # above) so that a stray warning can never block the artifact that 'deploy' publishes.
   validate:
     if: ${{ github.event_name == 'pull_request' || github.event_name == 'push' || github.event_name == 'workflow_dispatch' }}
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7
@@ -99,7 +101,8 @@ jobs:
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Setup Pages
         uses: actions/configure-pages@v6

.github/workflows/build-library.yml

@@ -44,7 +44,8 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     permissions:
       pull-requests: write
       contents: read
@@ -225,7 +226,8 @@ jobs:
           (github.event_name == 'workflow_dispatch' && startsWith(github.ref, 'refs/tags/')) }}
     needs: [ sign ]
     environment: nuget-release-gate
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     permissions:
       id-token: write
       contents: read

.github/workflows/build-samples-datasync-server-cosmosdb.yml

@@ -19,7 +19,8 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples-datasync-server.yml

@@ -19,7 +19,8 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples-todoapp-avalonia.yml

@@ -31,7 +31,8 @@ permissions:
 
 jobs:
   desktop:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7
@@ -60,7 +61,8 @@ jobs:
           --no-restore
 
   android:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples-todoapp-blazor-wasm.yml

@@ -19,7 +19,8 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples-todoapp-maui.yml

@@ -29,7 +29,8 @@ permissions:
 
 jobs:
   android:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples-todoapp-mvc.yml

@@ -19,7 +19,8 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples-todoapp-tutorial.yml

@@ -22,7 +22,8 @@ permissions:
 
 jobs:
   build-serverapp:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples-todoapp-uno.yml

@@ -30,7 +30,8 @@ permissions:
 
 jobs:
   android:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7
@@ -144,7 +145,8 @@ jobs:
           --no-restore
 
   browserwasm:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7
@@ -168,7 +170,8 @@ jobs:
           --no-restore
 
   desktop:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v7

.github/workflows/build-samples.yml

@@ -55,7 +55,8 @@ jobs:
       - todoapp-windows
       - todoapp-maui
       - todoapp-uno
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     steps:
       - name: Check sample build results
         run: |

.github/workflows/build-template.yml

@@ -26,7 +26,8 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     permissions:
       pull-requests: write
       contents: read
@@ -166,7 +167,8 @@ jobs:
           (github.event_name == 'workflow_dispatch' && startsWith(github.ref, 'refs/tags/')) }}
     needs: [ sign ]
     environment: nuget-release-gate
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     permissions:
       id-token: write
       contents: read

.github/workflows/stale-issues.yml

@@ -17,7 +17,8 @@ permissions:
 
 jobs:
   stale:
-    runs-on: ubuntu-latest
+    # Pinned to ubuntu-26.04 (not a floating label) so the runner image only changes when we choose.
+    runs-on: ubuntu-26.04
     permissions:
       issues: write
       pull-requests: write