ci: use ARM unit runners, overlap web builds, and reuse verifier fixtures (#23376)

* test: reuse isolated mobile bundle fixtures for verifier checks

* ci: run PR unit shards on ARM and overlap independent web builds

* docs: record controlled CI overlap and runner measurements

* test: observe WebRTC packets with the host clock

* ci: isolate Windows installer CIM probe from native test load

* docs: record native probe scheduling validation

---------

Co-authored-by: m4air <m4air@m4airs-Air.localdomain>

.github/workflows/ci-cache-warmup.yml

@@ -70,6 +70,22 @@ jobs:
         if: steps.typecheck-cache.outputs.cache-hit != 'true'
         run: pnpm run typecheck
 
+  warm-linux-arm:
+    runs-on: ubuntu-24.04-arm
+    timeout-minutes: 10
+    env:
+      ORCA_BACKGROUND_LAUNCH: '1'
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - uses: ./.github/actions/install-node-dependencies
+        with:
+          native-runtime: node
+          node-version: '24'
+      - name: Verify native cache is usable
+        run: node config/scripts/ensure-native-runtime.mjs --check-only
+
   warm-windows:
     strategy:
       fail-fast: false

.github/workflows/node-next-compat.yml

@@ -1,8 +1,8 @@
-name: Node next compatibility
+name: Scheduled x86 unit compatibility
 
 on:
   schedule:
-    # Full future-runtime coverage is useful, but not worth doubling every PR matrix.
+    # Keep current and future Node coverage on x86 while PR unit shards use ARM.
     - cron: '0 10 * * *'
   workflow_dispatch:
 
@@ -14,9 +14,13 @@ permissions:
   contents: read
 
 jobs:
-  # A cold cache would otherwise make all eight Node 26 shards compile the same native addons.
+  # Prime each Node ABI before its shards restore native modules.
   test_native_cache:
-    name: prepare test native cache node 26
+    name: prepare test native cache node ${{ matrix.node }}
+    strategy:
+      fail-fast: false
+      matrix:
+        node: ['24', '26']
     runs-on: ubuntu-latest
 
     steps:
@@ -28,10 +32,10 @@ jobs:
       - uses: ./.github/actions/install-node-dependencies
         with:
           native-runtime: node
-          node-version: '26'
+          node-version: ${{ matrix.node }}
 
   test:
     needs: [test_native_cache]
     uses: ./.github/workflows/unit-tests.yml
     with:
-      node_versions: '["26"]'
+      node_versions: '["24", "26"]'

.github/workflows/pr.yml

@@ -606,7 +606,7 @@ jobs:
     name: prepare test native cache node 24
     needs: [code_paths]
     if: needs.code_paths.outputs.native_cache_changed == 'true'
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04-arm
 
     steps:
       - name: Checkout
@@ -629,6 +629,7 @@ jobs:
     uses: ./.github/workflows/unit-tests.yml
     with:
       node_versions: '["24"]'
+      runner: ubuntu-24.04-arm
 
   # Why a separate job: the test needs a real Chrome, and the sharded `test` matrix
   # would pay for it on every shard to run one file in whichever shard it landed in.
@@ -897,6 +898,8 @@ jobs:
           exit "$status"
 
       - name: Project web client from renderer build
+        id: web-client
+        background: true
         run: pnpm run build:web-from-renderer
 
       # Why here and not inside "Build package inputs": this job assembles packaging inputs step by
@@ -908,7 +911,7 @@ jobs:
       - name: Build native components
         run: pnpm run build:native
 
-      - wait: linux-package-tools
+      - wait: [linux-package-tools, web-client]
 
       - name: Package unpacked app
         env:
@@ -1006,13 +1009,18 @@ jobs:
 
       # vitest runs here directly rather than through `pnpm test`, so the addon
       # assertions only hold once install-node-dependencies has rebuilt natives.
+      - name: Test Windows installer process probe
+        # Keep cold CIM startup out of the concurrent Electron/native process workload.
+        run: >-
+          pnpm exec vitest run --config config/vitest.config.ts
+          config/scripts/nsis-process-check.test.mjs
+
       - name: Test Windows-specific boundaries
         run: >-
           pnpm exec vitest run --config config/vitest.config.ts
           config/scripts/rebuild-native-deps.test.mjs
           config/scripts/rebuild-native-deps-windows-process-tree.test.mjs
           config/scripts/rebuild-native-deps-node-pty.test.mjs
-          config/scripts/nsis-process-check.test.mjs
           config/scripts/ensure-native-runtime-job-ownership.test.mjs
           config/scripts/verify-packaged-node-pty-job-ownership.test.mjs
           config/scripts/windows-pe-machine.test.mjs

.github/workflows/unit-tests.yml

@@ -8,13 +8,19 @@ on:
         required: true
         type: string
 
+      runner:
+        description: Hosted runner for the unit shards; relay integration keeps its x86 host.
+        required: false
+        default: ubuntu-latest
+        type: string
+
 permissions:
   contents: read
 
 jobs:
   test:
     name: tests node ${{ matrix.node }} ${{ matrix.shard }}/${{ matrix.shard_total }}
-    runs-on: ubuntu-latest
+    runs-on: ${{ inputs.runner }}
     strategy:
       fail-fast: false
       matrix:
@@ -78,7 +84,11 @@ jobs:
           if-no-files-found: warn
 
   relay_integration:
-    name: relay integration node ${{ fromJSON(inputs.node_versions)[0] }}
+    name: relay integration node ${{ matrix.node }}
+    strategy:
+      fail-fast: false
+      matrix:
+        node: ${{ fromJSON(inputs.node_versions) }}
     runs-on: ubuntu-latest
 
     steps:
@@ -90,7 +100,7 @@ jobs:
       - uses: ./.github/actions/install-node-dependencies
         with:
           native-runtime: node
-          node-version: ${{ fromJSON(inputs.node_versions)[0] }}
+          node-version: ${{ matrix.node }}
           cache-electron-package: 'true'
           cache-dependency-path: |
             pnpm-lock.yaml