Feature Request: Add PR count, explicit lines changed logs, and ai-tool log

[davidcuadrado-seatcode]

We are trying to mirror a specific Claude Code monitoring dashboard setup but are missing a few specific telemetry signals that this plugin doesn't emit yet.

Could you please add support for the following?

1. Pull Request metric: A pr.count counter metric (similar to commit.count) that increments when the agent executes a gh pr create command via the bash tool.
2. Explicit Lines Added/Removed Logs: Emitting explicit lines_added and lines_removed log events during the session.diff handler. Currently, the plugin updates the lines_of_code metrics, but having explicit log events with the line counts as attributes is needed for our backend queries.
3. ai-tool Log Event: Emitting an ai-tool log event alongside (or instead of) the existing tool_result log event when a tool execution completes.

Thanks!