fix: run wb through package manager in playwright web server

[exKAZUu]

Summary

• Generate Playwright webServer.command through the target package manager, e.g. yarn wb start --mode test or bun wb start --mode test.
• Update generated agent instructions to recommend the same package-manager-aware command.
• Share package-manager command detection via src/utils/packageCapabilities.ts.
• Update the related agent-instruction test expectation for Bun projects.

Why

• Target repositories install wb as a package dependency, so invoking wb directly can fail when the package binary directory is not on PATH.
• The generated command should still match the target repository package manager instead of hardcoding Yarn for Bun projects.

Testing

• yarn verify
• yarn vitest test/agentInstructions.test.ts

Notes

• yarn verify still reports 4 pre-existing Oxlint warnings unrelated to this change.

[gemini-code-assist]

Code Review

This pull request updates the Playwright configuration and agent instructions to invoke the wb command using yarn. The review feedback suggests using a dynamic packageManager variable instead of hardcoding yarn to support different package managers like Bun, and provides a suggestion to update the test suite to reflect this change.

[exKAZUu]

/gemini review

[gemini-code-assist]

Code Review

This pull request updates the Playwright configuration and agent instructions to ensure the wb command is executed via the project's package manager (bun or yarn). Feedback focuses on reducing code duplication by extracting the command string generation into a helper function and moving the package manager detection logic to a shared utility file to adhere to the DRY principle.

[exKAZUu]

/gemini review

[gemini-code-assist]

Code Review

This pull request centralizes the logic for determining the package manager command (bun or yarn) by introducing a getPackageManagerCommand utility. It refactors the Playwright configuration fixer and agent instruction generator to invoke wb commands through the appropriate package manager, ensuring consistency across different project environments. I have no feedback to provide as there were no review comments to evaluate.