chore(release): prepare 1.0.0-beta.6 (#3104)

* chore(release): prepare 1.0.0-beta.6

* ci(nix): harden flaky crate fetch handling

* ci(nix): drop magic cache and force fallback

* ci(nix): set explicit user-agent for crate fetch

* ci(nix): adopt determinate nix workflow stack

* ci(nix): add nix user-agent suffix for fetches

* ci(nix): add flakehub cache and align determinate actions

* ci(nix): pin determinate actions to release tags

* ci(nix): disable flakehub auth path in CI cache

* ci(nix): restore stable magic cache baseline

* ci(nix): trust local magic cache substituter

* ci(nix): stop forcing Node24 for JS actions

* ci(nix): drop manual localhost cache config

* ci(nix): adopt latest determinate flakehub stack

* ci(nix): record latest determinate workflow state

.github/workflows/nix.yml

@@ -38,41 +38,65 @@ concurrency:
   cancel-in-progress: true
 permissions:
   contents: read
+  id-token: write
 
 jobs:
   nix-validation:
     name: Nix Build & Check
     runs-on: ubuntu-latest
     timeout-minutes: 60
-    env:
-      FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: "true"
+    permissions:
+      contents: read
+      id-token: write
     steps:
       - name: Checkout repository
         uses: actions/checkout@v6
 
       - name: Install Nix
-        uses: cachix/install-nix-action@v31
+        uses: DeterminateSystems/determinate-nix-action@v3.21.0
         with:
-          github_access_token: ${{ secrets.GITHUB_TOKEN }}
-          extra_nix_config: |
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          extra-conf: |
             experimental-features = nix-command flakes
+            max-jobs = 1
 
-      - name: Setup Magic Nix Cache
-        uses: DeterminateSystems/magic-nix-cache-action@v13
+      - name: Cache Nix
+        uses: DeterminateSystems/flakehub-cache-action@v3.21.0
 
-      - name: Setup Flake Checker
+      - name: Check Nix Flake Inputs
         uses: DeterminateSystems/flake-checker-action@v12
+        with:
+          fail-mode: true
+          ignore-missing-flake-lock: false
 
       - name: Verify Flake
         run: |
           echo "Checking flake structure and evaluation..."
           nix flake show
-          nix flake check --print-build-logs
+          for attempt in 1 2 3; do
+            if nix flake check --print-build-logs --fallback --option fallback true; then
+              break
+            fi
+            if [ "$attempt" -eq 3 ]; then
+              echo "nix flake check failed after 3 attempts."
+              exit 1
+            fi
+            sleep $((attempt * 15))
+          done
 
       - name: Build RustFS
         run: |
           echo "Building the default package..."
-          nix build .#default --print-build-logs
+          for attempt in 1 2 3; do
+            if nix build .#default --print-build-logs --fallback --option fallback true; then
+              break
+            fi
+            if [ "$attempt" -eq 3 ]; then
+              echo "nix build failed after 3 attempts."
+              exit 1
+            fi
+            sleep $((attempt * 15))
+          done
 
       - name: Test Binary
         run: |