Runtime Dependencies: On-Demand Playwright Installation

[gsquared94]

Runtime Dependencies: On-Demand Playwright Installation

Summary

Install Playwright and Chromium to ~/.gemini/dependencies/ on first browser
task invocation.

Description

Browser automation requires ~200MB of dependencies. These should not be bundled
with the core package.

The installation flow:

1. Check ~/.gemini/dependencies/ for existing Playwright
2. If missing, inform user of disk footprint before installing
3. Run npm install playwright@<pinned-version> and
   npx playwright install chromium
4. Show progress during installation

Requires:

• Add getGlobalDependenciesDir() to
  storage.ts
• Add getFreePort() utility for CDP connection
• Installation logic in BrowserManager class

Acceptance Criteria

• Dependencies installed to managed directory on first use
• User informed of disk footprint before download
• Version pinning for reproducibility
• Graceful error when offline or npm unavailable

[gemini-cli]

This is an enhancement to implement on-demand installation of Playwright dependencies for the browser agent, affecting the platform.