Compact, useful tool summary by default

[jbellis]

Hi there, thanks for SessionWiki! I'm integrating it with Mjolnir.

I'd like to propose adopting the oh-my-pi "advisor" message summary's tool policy in SW. In this summary, tool calls are included as

1. Tool name
2. primary parameter (formatToolCallPrimaryArg, hardcodes a bunch of special cases like grep)
3. output line count
4. status (ok/error)

This gives arguably a more useful summary than --tools while being compact enough to make it the default behavior.

Happy to submit a PR!