Insights suggestions should be aware of existing user tooling

Problem

The insights report generates suggestions like "create a custom slash command for your dashboard workflow" or "set up hooks to auto-run tests after edits" without checking whether the user has already built those things. This makes the suggestions section feel generic and unhelpful for power users who have already invested in customizing their setup.

What insights should check before generating suggestions

1. Skills in ~/.claude/skills/ — global skills the user has already built
2. Skills loaded in session transcripts — the system-reminder at session start lists all available skills, including project-specific ones from various repos. The pipeline already has this data in the transcripts it analyzes.
3. CLAUDE.md rules — instructions the user has already codified (e.g., "run tests before commit" is already a rule, don't suggest adding it)
4. .claude/settings.json — hooks and other configuration already in place

Expected behavior

• Filter out suggestions for things that already exist (e.g., don't suggest "build a version bump skill" when bump-images/SKILL.md is loaded in sessions)
• Instead, surface suggestions for gaps — things the friction analysis identified that the user hasn't addressed yet
• Optionally, suggest improvements to existing skills/rules based on observed friction patterns (e.g., "your bump-images skill was used in 5 sessions but you still hit friction around tag naming — consider adding tag convention handling to it")