feat(cli): pic projects ls + §7 M3/track-complete docs

§7 M3 (part 3) — the ownership track becomes inspectable, completing M1–M3.

- server: GET /api/v1/admin/projects (projects_api) lists every project + its
  owned-group count (projects repo list_with_counts, one GROUP BY); behind the
  /admin middleware, like the groups list.
- CLI: pic projects ls (cmds/projects.rs + client projects_list); the
  apply_ownership plan-preview journey now also asserts projects ls (plat owns
  exactly 1 group; teamb listed).
- docs: design §7 + CLAUDE.md record M3 shipped and the whole §7 multi-repo
  ownership track (M1 claim · M2 attach ceiling · M3 preview + projects ls)
  COMPLETE; deferred = structural-divergence + declarative tree shape + per-env
  approval gating.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/design/groups-and-project-tool.md

@@ -783,8 +783,18 @@ within that subtree. `check_within_attach` requires the attach group be a **prop
 (so you can't apply the attach point itself, only its descendants) or an ancestor (inclusive) of an app node's
 group — resolved via `groups.ancestors`, enforced read-only before the claim in both `apply_owner` and
 `apply_tree`. Absent = instance root = no ceiling (default). Pinned by the `apply_ownership` journey's
-attach-ceiling case. **Deferred:** the plan-time cross-repo blast-radius preview + `pic projects ls` (M3); the
-**structural-divergence** detection of §6; declarative group create/reparent (lifting "groups pre-exist").
+attach-ceiling case.
+
+**Status — M3 shipped (plan preview + `pic projects ls`).** `pic plan` now carries the declaring `[project]`
+and returns an `ownership` preview per node — `claim` / `owned` / `conflict` (owner named) / `unclaimed`
+(pure `preview_ownership`, unit-tested) — plus, for a group node, the cross-repo **blast radius**: descendant
+apps owned by OTHER projects the change fans out to (`group_blast_radius`, a subtree CTE with per-group
+memoized nearest-claimed resolution). The attach ceiling is previewed at plan too (consistent with apply).
+Read-only `pic projects ls` lists every project + its owned-group count (`GET /api/v1/admin/projects`,
+`list_with_counts`). Pinned by the `apply_ownership` journey's plan-preview case. **With M3, the multi-repo
+ownership track (§7 M1–M3) is complete. Deferred (separate later work):** §6 structural-divergence detection
+(`--adopt-server-structure` / `--force-local-structure`); declarative group create/reparent (lifting "groups
+pre-exist"); per-env approval gating (`[project.environments]`).
 
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