[CI] fix: bump pixi

.github/workflows/ci.yml

@@ -108,7 +108,7 @@ jobs:
           fetch-depth: 0
       - uses: prefix-dev/setup-pixi@v0.9.4
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           frozen: true
           environments: lint
       - run: pixi run -e lint lint
@@ -128,7 +128,7 @@ jobs:
           fetch-depth: 0
       - uses: prefix-dev/setup-pixi@v0.9.4
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           frozen: true
           environments: ${{ matrix.package }}
       - name: Run tests

.github/workflows/claude-linkcheck-failure.yml

@@ -45,7 +45,7 @@ jobs:
       - uses: prefix-dev/setup-pixi@v0.9.4
         if: steps.api-key.outputs.configured == 'true'
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           run-install: false
 
       - name: Configure Git author

.github/workflows/claude-nightly-failure.yml

@@ -45,7 +45,7 @@ jobs:
       - uses: prefix-dev/setup-pixi@v0.9.4
         if: steps.api-key.outputs.configured == 'true'
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           run-install: false
 
       - uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0

.github/workflows/docs.yml

@@ -64,7 +64,7 @@ jobs:
           fetch-depth: 0  # history required to determine version
       - uses: prefix-dev/setup-pixi@v0.9.4
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           frozen: true
           environments: docs-${{ inputs.package }}
       - name: Build docs

.github/workflows/nightly-linkcheck.yml

@@ -34,7 +34,7 @@ jobs:
           fetch-depth: 0  # history required to determine version
       - uses: prefix-dev/setup-pixi@v0.9.4
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           frozen: true
           environments: docs-${{ matrix.package }}
       - name: Check links

.github/workflows/nightly.yml

@@ -42,7 +42,7 @@ jobs:
           fetch-tags: true
       - uses: prefix-dev/setup-pixi@v0.9.4
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           frozen: true
           environments: ${{ matrix.package }}
       - name: Run tests

.github/workflows/weekly-platform.yml

@@ -32,7 +32,7 @@ jobs:
           fetch-depth: 0
       - uses: prefix-dev/setup-pixi@v0.9.4
         with:
-          pixi-version: v0.68.0
+          pixi-version: v0.78.0
           frozen: true
           environments: ${{ matrix.package }}
       - name: Run tests

pixi.toml

@@ -1,17 +1,20 @@
 [workspace]
 name = "ess"
 channels = ["conda-forge"]
-platforms = ["linux-64", "osx-64", "osx-arm64", "win-64"]
+# Scipp requires macOS 14 or newer.
+platforms = [
+    "linux-64",
+    { platform = "osx-64", macos = "14.0" },
+    { platform = "osx-arm64", macos = "14.0" },
+    "win-64",
+]
 version = "2026.2.0"
+requires-pixi = ">=0.71.3"
 exclude-newer = "14d"
 
 [dependencies]
 python = "3.12.*"
 
-[system-requirements]
-# Scipp does not support older OSX versions.
-macos = "14.0"
-
 [pypi-exclude-newer]
 scipp = "0m"
 scippneutron = "0m"