Refactor workflows to use matrix for OS selection

Updated all GitHub Actions workflows to use a matrix strategy for OS selection, replacing direct 'runs-on: ubuntu-latest' with 'runs-on: ${{ matrix.os }}'. This change improves consistency and makes it easier to expand OS support in the future.

Author: rismay

.github/workflows/common-shell-docc.yml

@@ -16,7 +16,10 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
     defaults:
       run:
         shell: bash
@@ -80,11 +83,14 @@ jobs:
           path: _site
 
   deploy:
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
     needs: build
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     steps:
       - name: Deploy to GitHub Pages
         id: deployment

.github/workflows/common-shell-swift-format.yml

@@ -14,7 +14,10 @@ defaults:
 
 jobs:
   swift-format:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
     container: swift:6.1-noble
     steps:
       - name: Checkout (with submodules)

.github/workflows/common-shell-tests-commonshell-bench-tests.yml

@@ -10,7 +10,10 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
     container: swift:6.1-noble
     steps:
       - name: Checkout (with submodules)

.github/workflows/common-shell-tests-commonshell-cli-tests.yml

@@ -10,7 +10,10 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
     container: swift:6.1-noble
     steps:
       - name: Checkout (with submodules)

.github/workflows/common-shell-tests-commonshell-interactive-tests.yml

@@ -10,7 +10,10 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
     container: swift:6.1-noble
     steps:
       - name: Checkout (with submodules)

.github/workflows/common-shell-tests-commonshell-tests.yml

@@ -10,7 +10,10 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+    runs-on: ${{ matrix.os }}
     container: swift:6.1-noble
     steps:
       - name: Checkout (with submodules)