§7 M3 (part 1): `pic plan` now surfaces the ownership outcome BEFORE apply.
- plan / plan_owner / plan_tree take the declaring `[project]`; each result
carries an `ownership` preview (pure `preview_ownership`, unit-tested):
claim (unclaimed + project), owned (already this project), conflict (owned by
X — named), or unclaimed. A group node previews its OWN owner; an app node its
nearest claimed ancestor (read-only, on the pool).
- the attach-point ceiling (M2) is now previewed at plan too, so `pic plan`
outside the subtree fails early — consistent with apply.
- wire: PlanRequest / TreePlanRequest wrap { bundle, project } (project
`#[serde(default)]` → a pre-M3 CLI still plans); the plan DTOs + `pic plan`
gain an `ownership` row (mode-agnostic: shows in tsv + json).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>