feat(cli): add playwright attach command

[pavelfeldman]

Summary

• Adds a dedicated playwright attach <name> command replacing playwright open --attach="name"
• Session name defaults to the attach target name, or can be aliased with --session=<alias>
• Extracts shared startSession() helper for open and attach commands
• Adds explicitSessionName() utility to registry
• Updates tests for new attach command syntax

[github-actions]

Test results for "MCP"

5339 passed, 186 skipped

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Merge workflow run.

[github-actions]

Test results for "tests 1"

9 failed
❌ [default] › run-tests.spec.ts:226 › should show error message @vscode-extension
❌ [default] › run-tests.spec.ts:278 › should show soft error messages @vscode-extension
❌ [default] › run-tests.spec.ts:818 › should report project-specific failures @vscode-extension
❌ [default-reuse] › run-tests.spec.ts:226 › should show error message @vscode-extension
❌ [default-reuse] › run-tests.spec.ts:278 › should show soft error messages @vscode-extension
❌ [default-reuse] › run-tests.spec.ts:818 › should report project-specific failures @vscode-extension
❌ [default-trace] › run-tests.spec.ts:226 › should show error message @vscode-extension
❌ [default-trace] › run-tests.spec.ts:278 › should show soft error messages @vscode-extension
❌ [default-trace] › run-tests.spec.ts:818 › should report project-specific failures @vscode-extension

3 flaky

⚠️ [chromium-library] › library/video.spec.ts:358 › screencast › should capture navigation `@chromium-ubuntu-22.04-arm-node20`
⚠️ [chromium-library] › library/trace-viewer.spec.ts:1223 › should display language-specific locators `@chromium-ubuntu-22.04-node22`
⚠️ [firefox-page] › page/page-emulate-media.spec.ts:144 › should keep reduced motion and color emulation after reload `@firefox-ubuntu-22.04-node20`

38764 passed, 847 skipped

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Merge workflow run.