test: unflake mcp cli tests

[dgozman]

• Make cli depend on daemon.
• Use childProcess fixture to avoid zombies.

[github-actions]

Test results for "tests 1"

5 failed
❌ [playwright-test] › playwright.trace.spec.ts:1119 › trace:retain-on-first-failure should create trace if context is closed before failure in afterEach @macos-latest-node20
❌ [playwright-test] › reporter-markdown.spec.ts:158 › report with annotations @macos-latest-node20
❌ [playwright-test] › reporter.spec.ts:251 › merged › should not have internal error when steps are finished after timeout @macos-latest-node20
❌ [playwright-test] › ui-mode-test-network-tab.spec.ts:301 › should copy network request @macos-latest-node20
❌ [playwright-test] › ui-mode-test-network-tab.spec.ts:264 › should toggle sections inside network details @windows-latest-node20

2 flaky

⚠️ [webkit-page] › page/page-autowaiting-basic.spec.ts:79 › should await form-post on click `@webkit-ubuntu-22.04-node20`
⚠️ [playwright-test] › ui-mode-trace.spec.ts:185 › should show snapshots for steps `@macos-latest-node20`

34666 passed, 695 skipped

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Merge workflow run.

[github-actions]

Test results for "MCP"

9 failed
❌ [webkit] › mcp/snapshot-mode.spec.ts:58 › should respect --snapshot-mode=incremental @mcp-windows-latest
❌ [chrome] › mcp/cli.spec.ts:267 › save as › screenshot --full-page @mcp-macos-15
❌ [chromium] › mcp/cli.spec.ts:162 › core › dialog-accept @mcp-macos-15
❌ [chromium] › mcp/cli.spec.ts:267 › save as › screenshot --full-page @mcp-macos-15
❌ [chromium] › mcp/cli.spec.ts:342 › devtools › tracing-start-stop @mcp-macos-15
❌ [firefox] › mcp/cli.spec.ts:267 › save as › screenshot --full-page @mcp-macos-15
❌ [firefox] › mcp/cli.spec.ts:342 › devtools › tracing-start-stop @mcp-macos-15
❌ [webkit] › mcp/cli.spec.ts:267 › save as › screenshot --full-page @mcp-macos-15
❌ [webkit] › mcp/snapshot-mode.spec.ts:58 › should respect --snapshot-mode=incremental @mcp-macos-15

3097 passed, 300 skipped

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Merge workflow run.