devops: bump workers count 2->4 on CI

[yury-s]

Standard runners for public repositories now have 4 CPUs:

Virtual machine / container	Processor (CPU)	Memory (RAM)	Storage (SSD)	Architecture	Workflow label
Linux	1	5 GB	14 GB	x64	ubuntu-slim
Linux	4	16 GB	14 GB	x64	ubuntu-latest, ubuntu-24.04, ubuntu-22.04
Windows	4	16 GB	14 GB	x64	windows-latest, windows-2025, windows-2022
Linux	4	16 GB	14 GB	arm64	ubuntu-24.04-arm, ubuntu-22.04-arm
Windows	4	16 GB	14 GB	arm64	windows-11-arm
macOS	4	14 GB	14 GB	Intel	macos-13, macos-15-intel
macOS	3 (M1)	7 GB	14 GB	arm64	macos-latest, macos-14, macos-15, macos-26 (public preview)

[github-actions]

Test results for "tests 1"

4 failed
❌ [playwright-test] › aria-snapshot-file.spec.ts:109 › should generate snapshot name @macos-latest-node20
❌ [playwright-test] › playwright.spec.ts:555 › should work with video.path() throwing @macos-latest-node20
❌ [playwright-test] › playwright.unhandled.spec.ts:51 › should produce uncaughtException when context.route raises @macos-latest-node20
❌ [playwright-test] › reporter-html.spec.ts:1037 › merged › should have link for opening HTML attachments in new tab @macos-latest-node20

2 flaky

⚠️ [playwright-test] › runner.spec.ts:124 › should ignore subprocess creation error because of SIGINT `@macos-latest-node20`
⚠️ [playwright-test] › ui-mode-trace.spec.ts:426 › should work behind reverse proxy `@macos-latest-node20`

34410 passed, 696 skipped

---

Merge workflow run.

[github-actions]

Test results for "MCP"

9 failed
❌ [chrome] › mcp/session-log.spec.ts:136 › session log should update user action @mcp-macos-15
❌ [chromium] › mcp/core.spec.ts:167 › browser_resize @mcp-macos-15
❌ [chromium] › mcp/screenshot.spec.ts:100 › browser_take_screenshot (type: jpeg) @mcp-macos-15
❌ [chromium] › mcp/screenshot.spec.ts:179 › browser_take_screenshot (filename is empty string) @mcp-macos-15
❌ [chromium] › mcp/screenshot.spec.ts:292 › browser_take_screenshot (fullPage: true) @mcp-macos-15
❌ [chromium] › mcp/video.spec.ts:43 › should work with { saveVideo } (isolated) @mcp-macos-15
❌ [chromium] › mcp/video.spec.ts:63 › should work with recordVideo (persistent) @mcp-macos-15
❌ [webkit] › mcp/planner.spec.ts:131 › planner_setup_page with dependencies @mcp-macos-15
❌ [webkit] › mcp/sse.spec.ts:233 › sse transport shared context @mcp-macos-15

2813 passed, 116 skipped

---

Merge workflow run.

[yury-s]

Some improvement over the previous numbers (left - before / right - after):

[Skn0tt]

neat!