"Add pitboss start universal entry + iteration wizard

[jrf227]

Summary

Three new top-level commands and a guided wizard:

• pitboss start — universal entry point. Auto-detects .pitboss/; routes new users into setup +
  chains to play, existing users into an iteration wizard (continue/sweep/new-plan).
• pitboss config (alias: setup) — multi-step config wizard with explanatory screens for each knob
  (models, budget, sweeps, auditor, tests). On an existing workspace, opens to a summary screen
  pre-populated from disk; user can save or step back through to edit. Writes an exhaustive
  self-documenting config.toml (no invisible defaults).
• pitboss nuke — deletes .pitboss/ after y/N confirmation.

The new-plan path inside pitboss start drives an in-TUI interview (1-5 / 5-10 / 10-20 / as-many
question ranges) against the planner agent and shows the generated phase list with run/wait/terminate
options.

Why

rebuy / sweep / hand-edit deferred.md. This is purely additive — every existing command keeps its
signature and behavior.

Tests

• 713 tests passing (was 707; +6 new for nuke, config round-trip, scroll math)
• cargo clippy --all-targets -D warnings clean
• cargo fmt --check clean
• No snapshot drift in src/{prompts,tui,grind}/snapshots/

Test plan

• cargo install --path . --force
• pitboss config in a fresh dir → walk 6 steps → confirm .pitboss/config.toml has every section
• pitboss start in the same dir → iteration wizard → New plan → interview → review screen → Run
• pitboss setup (alias) still works
• pitboss nuke → y deletes .pitboss/; n leaves it
• pitboss play --dry-run unchanged from main
  EOF
  )"

[jrf227]

LMK what you think