[TypeSpecValidationAll] Improve UI of matrix jobs (Azure#31341)

- Fixes Azure#31339

.github/workflows/typespec-validation-all.yaml

@@ -34,21 +34,26 @@ on:
 
 jobs:
   typespec-validation-all:
-    name: TypeSpec Validation All
+    # Use short name to maximize space for parameters in UI
+    name: TSV
+
     strategy:
+      # Validate all specs, even if one job fails early
       fail-fast: false
+      # Sort matrix elements from "most important" to "least important" for the best grouping and UI
+      # Keep matrix values short, to maximize number of parameters shown in UI
       matrix:
-        os: [ubuntu-latest, windows-latest]
+        # When triggered by schedule, validate both the default branch and typespec-next
+        # Use the placeholder string "default" instead of passing "" directly, since the latter gets ignored by
+        # the GitHub Jobs UI.
+        ref: ${{ fromJSON(github.event_name == 'schedule' && '["default", "next"]' || '["default"]') }}
+        os: [ubuntu, windows]
         # shards must start at 0 and increment by 1
         shard: [0, 1, 2]
         # total-shards must be an accurate count of the number of shards
         total-shards: [3]
-        # When triggered by schedule, validate both the default branch and typespec-next
-        # Use the placeholder string "default" instead of passing "" directly, since the latter gets ignored by
-        # the GitHub Jobs UI.
-        ref: ${{ fromJSON(github.event_name == 'schedule' && '["default", "typespec-next"]' || '["default"]') }}
 
-    runs-on: ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}-latest
 
     steps:
       - name: Enable git long paths
@@ -58,7 +63,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           # Convert placeholder string 'default' to '', which tells the action to checkout the default ref.
-          ref: ${{ matrix.ref != 'default' && matrix.ref || '' }}
+          ref: ${{ matrix.ref == 'next' && 'typespec-next' || '' }}
 
       - name: Setup Node 20 and run `npm ci`
         uses: ./.github/actions/setup-node-npm-ci