Add Timeout Parameter to Click Action

Summary

Adds timeout parameter to the click command, exposing Playwright's built-in timeout option to prevent indefinite hangs on problematic pages.

Why this is Critical for AI Agents

AI agents using agent-browser get stuck indefinitely when clicking elements on:

• Pages with slow/broken JavaScript that never completes event handlers
• Elements with async handlers that don't resolve
• SPAs with navigation logic that hangs
• Pages with infinite loading states

Blockers:

• Production agents cannot afford indefinite hangs - they need fail-fast behavior
• Current workaround (external timeouts) doesn't cleanly abort Playwright operations
• Other automation frameworks (Selenium, Puppeteer) all expose timeout controls

Changes

CLI (cli/src/commands.rs):

agent-browser click @e1 --timeout 500  # Fail after milliseconds instead of hanging

JSON Protocol (src/protocol.ts, src/types.ts):

{"action": "click", "selector": "@e1", "timeout": 500}

• Added extract_timeout() helper that properly parses and filters --timeout flag
• Prevents flag leakage into text content for other commands
• Timeout validation via Zod (positive numbers only)
• Pass-through to Playwright's native click({ timeout }) option
• Updated skills/agent-browser/SKILL.md with example

Tests Added:

• Protocol validation: accept valid timeout, reject negative values
• All existing tests pass: 213 passed, 9 skipped

Testing

# Test timeout behavior
agent-browser open https://slow-site.example.com
agent-browser click "#broken-button" --timeout 1000  # Fails fast instead of hanging

# Without timeout (default Playwright behavior)
agent-browser click "#normal-button"  # Works as before

Breaking Changes

None. Timeout is optional and backward compatible with existing usage.