ci(e2e): run the macOS Electron suite as two shards (#1707)

macOS runners are the scarcest on this account, so macOS now runs the
Electron E2E suite as two Playwright shards instead of three; Ubuntu and
Windows keep three. macOS shards get a 40-minute timeout. The summary job
needed no change because it reads each shard's total from its report.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/e2e-tests.yaml

@@ -42,17 +42,26 @@ jobs:
         # The sequential Electron suite is split into Playwright shards (one
         # runner each, split by spec file). Measured on 2026-09-26, a third of
         # the suite is 6-12 minutes of test time on top of 3-7 minutes of
-        # setup, so 30 minutes leaves room for retries on every OS.
-        timeout-minutes: 30
+        # setup. macOS uses two shards because its runners are the scarcest:
+        # three macOS shards per run queued for 45-57 minutes on master. Half
+        # of the suite is about 15 minutes of test time on macOS, so it gets
+        # a longer timeout to leave room for retries.
+        timeout-minutes: ${{ matrix.os == 'macos-latest' && 40 || 30 }}
         env:
             IPTVNATOR_ALLOW_PRIVATE_NETWORK_URLS: '1'
             NX_SKIP_NX_CACHE: true
         strategy:
             fail-fast: false
             matrix:
-                os: [ubuntu-latest, macos-latest, windows-latest]
-                shard: [1, 2, 3]
-                shard-total: [3]
+                include:
+                    - { os: ubuntu-latest, shard: 1, shard-total: 3 }
+                    - { os: ubuntu-latest, shard: 2, shard-total: 3 }
+                    - { os: ubuntu-latest, shard: 3, shard-total: 3 }
+                    - { os: macos-latest, shard: 1, shard-total: 2 }
+                    - { os: macos-latest, shard: 2, shard-total: 2 }
+                    - { os: windows-latest, shard: 1, shard-total: 3 }
+                    - { os: windows-latest, shard: 2, shard-total: 3 }
+                    - { os: windows-latest, shard: 3, shard-total: 3 }
 
         steps:
             - uses: actions/checkout@v7

docs/architecture/validation-map.md

@@ -146,8 +146,9 @@ After an E2E run, generate the semantic summary with:
 pnpm run coverage:e2e:summary
 ```
 
-CI runs the Electron suite as three Playwright shards per OS
-(`--shard=<n>/3`, split by spec file because the suite is sequential). Each
+CI runs the Electron suite as Playwright shards (`--shard=<n>/<total>`, split
+by spec file because the suite is sequential): three shards on Ubuntu and
+Windows, two on macOS, whose runners are the scarcest and queued longest. Each
 shard uploads `playwright-report-electron-<os>-<n>`; the follow-up
 `Electron E2E summary` job downloads the shards of each OS into their own
 directory and runs the summary per OS with `--input=<directory>` and