ci: accecelerate pipeline (#2078)

* enable concurrency

pr

* do not run build on draft PRs

pr

* enable fail-fast for build workflows

.github/workflows/nix.yml

@@ -8,12 +8,18 @@ on:
       - "flake.lock"
   pull_request:
     branches: ["main", "develop"]
+    types: [opened, synchronize, reopened, ready_for_review]
     paths:
       - "**/*.nix"
       - "flake.lock"
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   check-full-shell:
+    if: github.event_name != 'pull_request' || !github.event.pull_request.draft
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5