feat(orchestrator): W3 artifacts tree, ancestry, gates and token-free cleanup

Artifacts show the branch tree with ancestry and gate marks. The cleanup runner calls pkgmgr branch cleanup with its real argv and parses its repos[*].items output, refuses any plan with a remote-branch action, marks an item done only when pkgmgr reports it done, and offers no delete for a branch a worktree holds. Every text states what the pkgmgr command does to volumes. Committed below the bar on the operator's word 2026-11-12 (no further per-bundle tests, one gate after the merge): the W3 e2e never ran; the client switches to --local once pkgmgr ships it.

🎯 Fix: 90 %
💥 Break: 6 %
💸 Cost: 30 %
⏱️ Time: 40 %
🛡️ Security: 100 %
🏆 Score: 100
🚦 Gate: ⛔ break 6 % > 5

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

orchestrator/kvb_orchestrator/artifacts.py

@@ -8,6 +8,7 @@ from pathlib import Path
 
 from .records import epoch, iso_epoch, read_json, shown
 from .register import ENDED, status_of
+from .signed import signing
 from .tree import inside, owns
 
 PUSH = re.compile(r"\b(?:push|gipsn|git-sign-push)\b")
@@ -105,7 +106,8 @@ def enrich(scan: dict, tasks: dict[str, dict], reviews: list[dict], touched: Tou
             shared = sorted(files[a] & files[b])
             if shared:
                 overlaps.append({"a": a, "b": b, "count": len(shared), "files": shared[:SHARED_SHOWN]})
-        merges = [{"from": item["name"], "into": item["merged_into"] or entry.get("default") or "", "by": item["merged_by"]} for item in entry["branches"] if item["merged_by"]]
+        default = entry.get("default") or ""
+        merges = [{"from": item["name"], "into": default if signing.names_default(item["merged_into"], default) else item["merged_into"] or default, "by": item["merged_by"]} for item in entry["branches"] if item["merged_by"]]
         repos.append({**entry, "branches": branches, "overlaps": overlaps, "merges": merges})
     loose = [{"task": task, "title": shown(row.get("title")), "status": status_of(row), "artefacts": artefacts_of(task, row)} for task, row in sorted(tasks.items()) if task not in placed and artefacts_of(task, row)]
     return {**scan, "repos": repos, "tasks": loose}