shed onboard (5-min interactive setup for new users)

[CasterlyGit]

What this adds

shed onboard — a 5-minute interactive setup walking through privacy choices, memory bootstrapping, and first-day expectations. For users who aren't Tarun.

Spec

1. Detect first-time install (no ~/.shed/ exists)
2. Walk through:
   • Privacy posture: strict (default), balanced, permissive
   • Auto-apply defaults: per-loop yes/no
   • Memory bootstrap: import existing CLAUDE.md, scan recent git history for patterns
   • Sync: enable now, later, never
3. Generate personalized config + initial CLAUDE.md scaffold
4. Run a guided first session showing how the morning brief works (mock data)
5. Schedule a "1-week check-in" via launchd that triggers a summary of what shed learned in the first week

Acceptance

• A first-time user with no shed knowledge can set up in < 10 min
• First-week summary feels useful (proven by user testing — see docs: clarify public verification path and operating boundaries #33 acceptance)
• Privacy choices are clearly explained, defaults are most restrictive

Cross-cutting

• Required for any external user (docs: clarify public verification path and operating boundaries #33 docs site assumes this exists)