.github/workflows: Remove 25.11 workflows (#537382)

.github/labeler-no-sync.yml

@@ -22,17 +22,6 @@
               - doc/**/*
               - nixos/doc/**/*
 
-"backport release-25.11":
-  - all:
-      - changed-files:
-          - any-glob-to-any-file:
-              - .github/actions/**/*
-              - .github/workflows/*
-              - .github/labeler*.yml
-              - ci/**/*.*
-              - maintainers/github-teams.json
-      - base-branch: ['master']
-
 "backport release-26.05":
   - all:
       - changed-files:

.github/workflows/periodic-merge-24h.yml

@@ -31,12 +31,6 @@ jobs:
       max-parallel: 1
       matrix:
         pairs:
-          - from: release-25.11
-            into: staging-next-25.11
-          - from: staging-next-25.11
-            into: staging-25.11
-          - from: release-25.11
-            into: staging-nixos-25.11
           - from: release-26.05
             into: staging-next-26.05
           - from: staging-next-26.05