fix: add MCP tool annotations

[zxyasfas]

Summary

Adds MCP tool annotations to BrowserMCP tool definitions so clients can distinguish read-only inspection tools from browser actions that can change page state.

Changes

• Extends the local tool schema with optional MCP annotations.
• Marks snapshot, hover, wait, console logs, and screenshot tools as read-only.
• Marks click, drag, type, select option, and press key tools as destructive.
• Marks browser navigation history tools as non-destructive navigation actions.

Fixes #162.

Validation

• git diff --check
• Could not run the package typecheck in this standalone checkout because package.json references workspace packages via workspace:*.