feat(orchestrator): Agents and Artifacts views with spawn tree, orbit, 3D and signed branch deletes

Phase 4 of requirement 001. Agents and Artifacts each offer Orbit, Chord, Swimlane, Tree and 3D: the spawn tree (page-spawn.js) and the artifacts orbit (page-artifacts.js, kvb_orchestrator/artifacts.py) replace the "folgt" placeholders, 3D runs on the vendored 3d-force-graph and three.js (MIT, LICENSE files kept, served from the image under the unchanged CSP), and a Bootstrap Icons sprite (icons.py, MIT) replaces the emoji glyphs, also in the meditation page.

Signed branch deletes: the Tree view offers a delete only for merged-clean branches without a gc skip reason; the operator signs the exact item with the passkey, the hub writes a job without any command (kvb_orchestrator/cleanup.py), and the host path unit runs client/cleanup.py, which verifies the signature, dry-runs pkgmgr branch cleanup for that exact branch, refuses patterns, option names, changed tips, other worktrees and plans naming other branches, deletes, and rewrites the branch tree. pkgmgr runs with core.hooksPath=/dev/null, core.fsmonitor=false and the config hook events disabled through GIT_CONFIG_COUNT, because the cwd is a repository agents can write and pkgmgr releases before 4c8b137 delete without scan mode (test with a positive control that both hook kinds fire without it).

3D labels go into the tooltip as a text node: the vendored tooltip renders a string label as HTML.

Tests: 503 OK, Chromium (CDP) and Firefox (BiDi) walks over every screen at three widths.

MEDUSA acceptances (kvb-think-criticize skeptic 2026-11-07): WEB-FLASK-004 view.py:135 (file template, autoescape on, state via tojson), MEDUSA-MM-SCAN-058 server.py:69/:85 (substring pla in --templates and Places), RH005 client/cleanup.py:199 (raise SystemExit(main())), B704 icons.py:45 (sprite baked into the image, names checked against it), EXA002 page-artifacts.js:221 (openAgent only opens the drawer), STG002 page-constants.js:64 (U+2212 in a static label), PL002 page-graph3d.js:44 (CSS class space-tools; the real tooltip sink fixed), B603 client/cleanup.py:75 (argv without shell; hook hole closed).

🎯 Fix: 92 %
💥 Break: 5 %
💸 Cost: 100 %
⏱️ Time: –
🛡️ Security: 100 %
🏆 Score: 87
🚦 Gate: ✅ 90/5, cost and time <= 100, security 100 %

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

docs/requirements/001-agent-orchestrator.md

@@ -118,8 +118,8 @@ from three views down to any agent, branch or artefact.
       items, and "Löschen" needs the operator signature (`/api/sign`).
       Rejected: a second click without signature, one click without preview.
     - **Execution**: the orchestrator writes a signed job into a host
-      directory; a systemd user path unit runs `pkgmgr branch gc --apply` for
-      exactly those items and writes the result back. Rejected: an
+      directory; a systemd user path unit runs `pkgmgr branch cleanup --apply
+      --local` for exactly those items and writes the result back. Rejected: an
       `operator.py` row (not direct).
 22. **Organisation update**: a new skill `kvb-org-update` tells every agent
     and client which skills changed and how to use them, as one
@@ -348,8 +348,8 @@ flowchart TD
       and tip sha per item, no command) into a host-mounted job directory and
       holds no git, token or key.
 - [ ] A systemd user path unit verifies the signature on the host and runs
-      `pkgmgr branch gc --apply --local` for exactly the signed items, matched
-      exactly, never as a pattern; `--local` removes the worktree, the local
+      `pkgmgr branch cleanup --apply --local` for exactly the signed items,
+      matched exactly, never as a pattern; `--local` removes the worktree, the local
       branch, the compose stack without `-v` and its images, never a remote
       branch, and needs no SSH key.
 - [ ] The unit refuses, and changes nothing for, an item whose tip or state