/insights: per-project recommendations instead of mixing everything together

Hey! Love the /insights feature, spent some time reading through my report and there's genuinely useful stuff in there.

One thing though. I work across several very different projects. One is pure Bash scripts with some Python, another is Java/Spring Boot with Oracle, another has no Spring at all. The report mixes all sessions together and gives recommendations that assume everything is the same stack.

For example it suggested adding mvn compile as a post-edit hook and described my project as "Java/Spring Boot with Oracle". That's true for one project but makes zero sense for my VPN infra repo that's all shell scripts. Same with the CLAUDE.md suggestions, they're written as universal rules but really only apply to one of my projects.

What I'd actually want is something like this. It can still be one report, that's totally fine, but the recommendations should work on two levels. If there's a pattern across all my projects (like "don't add Co-Authored-By" or "prefer simpler approaches") then show it as a global thing and maybe suggest how to set it up globally in settings or global CLAUDE.md. But if something is specific to one project's stack then just say so. Like "for your Java/Spring project add this hook" instead of just "add this hook" as if I only have one project.

The data is already there since sessions are tied to working directories. It's just the analysis part that blends everything into one.