Add daily auto-update workflow with shared build script

.gitea/workflows/check-flake.yaml

@@ -6,6 +6,8 @@ env:
   DEBIAN_FRONTEND: noninteractive
   PATH: /run/current-system/sw/bin/
   XDG_CONFIG_HOME: ${{ runner.temp }}/.config
+  ATTIC_ENDPOINT: ${{ vars.ATTIC_ENDPOINT }}
+  ATTIC_TOKEN: ${{ secrets.ATTIC_TOKEN }}
 
 jobs:
   check-flake:
@@ -16,34 +18,5 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: Configure Attic cache
-        run: |
-          attic login local "${{ vars.ATTIC_ENDPOINT }}" "${{ secrets.ATTIC_TOKEN }}"
-          attic use local:nixos
-
-      - name: Check Flake
-        run: nix flake check --all-systems --print-build-logs --log-format raw --show-trace
-
-      - name: Build all systems
-        run: |
-          nix eval .#nixosConfigurations --apply 'cs: builtins.attrNames cs' --json \
-            | jq -r '.[]' \
-            | xargs -I{} nix build ".#nixosConfigurations.{}.config.system.build.toplevel" --no-link --print-build-logs --log-format raw
-
-      - name: Push to cache
-        run: |
-          set -euo pipefail
-          # Get all system toplevel store paths
-          toplevels=$(nix eval .#nixosConfigurations --apply 'cs: map (n: "${cs.${n}.config.system.build.toplevel}") (builtins.attrNames cs)' --json | jq -r '.[]')
-          echo "Found $(echo "$toplevels" | wc -l) system toplevels"
-          # Expand to full closures, deduplicate, and filter out paths that are:
-          # - already signed by cache.nixos.org (available upstream)
-          # - smaller than 0.5MB (insignificant build artifacts)
-          paths=$(echo "$toplevels" \
-            | xargs nix path-info -r --json \
-            | jq -r '[to_entries[] | select(
-                (.value.signatures | all(startswith("cache.nixos.org") | not))
-                and .value.narSize >= 524288
-              ) | .key] | unique[]')
-          echo "Pushing $(echo "$paths" | wc -l) unique paths to cache"
-          echo "$paths" | xargs attic push local:nixos
+      - name: Build and cache
+        run: bash .gitea/scripts/build-and-cache.sh