chore: add Renovate config and retarget the CI platform matrix

.github/renovate.json5

@@ -0,0 +1,55 @@
+{
+  $schema: 'https://docs.renovatebot.com/renovate-schema.json',
+  extends: [
+    'config:recommended',
+    'github>rstackjs/renovate:security',
+    'schedule:weekly',
+    'helpers:pinGitHubActionDigests',
+  ],
+  // E2E fixtures deliberately pin the published toolchain versions the suites
+  // run against; bumping them is a manual, E2E-verified decision.
+  ignorePaths: ['**/node_modules/**', 'packages/vscode/tests/**'],
+  packageRules: [
+    // Use chore as semantic commit type for commit messages
+    {
+      matchPackageNames: ['**'],
+      semanticCommitType: 'chore',
+      // always bump package.json
+      rangeStrategy: 'bump',
+    },
+    {
+      groupName: 'all patch dependencies',
+      groupSlug: 'all-patch',
+      matchUpdateTypes: ['patch'],
+      matchPackageNames: ['**'],
+    },
+    // The Rstack toolchain is what this repo exists to support and it ships
+    // every few days, so it opts out of the weekly window entirely: a PR is
+    // opened on the next run after a release. `schedule:weekly` still governs
+    // everything else, and `github>rstackjs/renovate:security` already waives
+    // the release-age cooldown for the same set. Listed after `all-patch` so
+    // these land in their own PR instead of the weekly patch roll-up.
+    //
+    // This includes `@rslint/core`, `@rstest/core` and `rstack`, whose ranges
+    // sit alongside the runtime `SUPPORT_MATRIX` (shared/versionCheck.ts).
+    // That matrix is a floor, not a pin: raising a devDependency does not move
+    // it. Lowering the floor stays a deliberate, separate edit.
+    {
+      groupName: 'rstack toolchain',
+      groupSlug: 'rstack',
+      matchPackageNames: [
+        '@rsbuild/**',
+        '@rsdoctor/**',
+        '@rslib/**',
+        '@rslint/**',
+        '@rspack/**',
+        '@rspress/**',
+        '@rstackjs/**',
+        '@rstest/**',
+        'rsbuild-plugin-**',
+        'rstack',
+      ],
+      schedule: ['at any time'],
+    },
+  ],
+}

.github/workflows/ci.yml

@@ -14,11 +14,16 @@ permissions:
   contents: read
 
 jobs:
-  # ======== linux ========
-  test-linux:
-    name: Test (ubuntu-latest)
+  # ======== lint + unit tests: Linux only ========
+  # Nothing under test here branches on `process.platform`: the three places
+  # that do (`detection.ts` bin names, `stacks/lint/utils.ts` platform
+  # packages, `stacks/test/projectCoverage.ts` path casing) are only reachable
+  # when the host *is* that platform, so a second OS would re-run identical
+  # assertions. The Windows branches are covered by the Windows E2E job below.
+  ut:
+    name: UT (ubuntu-latest)
     runs-on: ubuntu-latest
-    timeout-minutes: 30
+    timeout-minutes: 20
 
     steps:
       - name: Checkout
@@ -51,33 +56,21 @@ jobs:
       - name: Unit Test
         run: pnpm run test:unit
 
-      # `@vscode/test-electron` downloads a full VS Code into
-      # `packages/vscode/.vscode-test`. Cache only the immutable distribution
-      # directories, keyed on the extension manifest (which carries
-      # `engines.vscode`); the restore-keys fallback keeps older downloads
-      # available while `version: 'stable'` moves forward.
-      - name: Cache VS Code Download
-        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
-        with:
-          path: packages/vscode/.vscode-test/vscode-*
-          key: vscode-test-${{ runner.os }}-${{ hashFiles('packages/vscode/package.json') }}
-          restore-keys: |
-            vscode-test-${{ runner.os }}-
-
-      # The E2E fixtures install published npm packages at test time
-      # (tests/e2e/setupFixtures.mjs, invoked by test:e2e), so this step needs
-      # network access. The VS Code Extension Host needs a display on Linux,
-      # hence xvfb (preinstalled on GitHub-hosted Ubuntu runners).
-      - name: E2E Test
-        run: xvfb-run -a pnpm run test:e2e
-
-  # ======== windows ========
-  # A dedicated GitHub-hosted Windows job: upstream rslint notes the VS Code
-  # extension E2E suite is unreliable on self-hosted Windows runners.
-  test-windows:
-    name: Test (windows-latest)
-    runs-on: windows-latest
+  # ======== E2E: Windows + macOS, no Linux ========
+  # These are the platforms the extension is actually used on, and the only
+  # ones upstream rstest runs its ported VS Code suites on. Linux is excluded
+  # deliberately: the Extension Host needs xvfb there, and inotify reports a
+  # non-atomic file rewrite as separate truncate/write events, so fixture edits
+  # in the watch-mode suites race the watcher in a way no user hits. Do not add
+  # a Linux E2E job back without also making every fixture edit atomic.
+  e2e:
+    name: E2E (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
     timeout-minutes: 40
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest, macos-latest]
 
     steps:
       - name: Checkout
@@ -101,12 +94,11 @@ jobs:
       - name: Build
         run: pnpm run build
 
-      - name: Lint
-        run: pnpm run lint
-
-      - name: Unit Test
-        run: pnpm run test:unit
-
+      # `@vscode/test-electron` downloads a full VS Code into
+      # `packages/vscode/.vscode-test`. Cache only the immutable distribution
+      # directories, keyed on the extension manifest (which carries
+      # `engines.vscode`); the restore-keys fallback keeps older downloads
+      # available while `version: 'stable'` moves forward.
       - name: Cache VS Code Download
         uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         with:
@@ -115,5 +107,8 @@ jobs:
           restore-keys: |
             vscode-test-${{ runner.os }}-
 
+      # The E2E fixtures install published npm packages at test time
+      # (tests/e2e/setupFixtures.mjs, invoked by test:e2e), so this step needs
+      # network access.
       - name: E2E Test
         run: pnpm run test:e2e