fix(issue-10,11,13,15): complete agy purge, orchestrator purge, workspace-anchored registry

Issue #10 - agy purge_artifacts left resumable pieces behind: it now also
removes the SQLite sidecars (-wal/-shm/-journal), the title annotation and
the presence lock (the lock only once no live process references the
conversation), and residual_artifacts() reports anything under
~/.gemini/antigravity-cli still carrying the uuid.

Issue #13 - the orchestrator has no herdr_sessions row, so its conversation
could not be purged by any skill. `lib_py.agents purge <agent|auto> <uuid>`
resolves the adapter from what is on disk (orchestrator_uuids stores bare
uuids), refuses while a live process names the uuid (conversation_in_use:
process list minus the caller's own lineage, plus lsof), and prints what it
purged. `orc_onboard.sh --remove <uuid> --purge-conversation --yes [--agent]`
runs it before the registry update so a refusal changes nothing (exit 4
without --yes, 5 while in use).

Issue #11 - "Successfully removeed": conjugate add/remove explicitly.

Issue #15 - the job registry and audit log followed the caller's cwd, so the
pytest suite (create_session.sh with its default onboarding job, run from the
repo root) had left 593 test records in the real .mam/jobs. Defaults now
resolve MAM_JOBS_DIR / DELEGATE_JOB_LOGS_DIR, then $WORKSPACE_ROOT/.mam/...,
then the cwd (mqtt_common.default_registry_dir / get_logs_dir; registry.py,
publish_event.py, service.py, create_session.sh, stop_session.sh); the
sandbox fixture pins both. The tier suites that used to leak now leave the
real registry untouched (881 records before and after).

Tests: test_issue10_13_purge.py (13), test_issue15_registry_isolation.py (7);
T-O13 pins the corrected message; the R1 helper test and B-9 logs-dir test
now assert the workspace-anchored contract; publish_event snapshot updated.

Refs #10 #11 #13 #15

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

.agents/skills/multi-agent-mux-stop/scripts/stop_session.sh

@@ -148,7 +148,7 @@ if [ -n "$DELEGATE_JOB_ID" ]; then
   local_info=$(python3 -c "
 import sys, json, os
 jid = '$DELEGATE_JOB_ID'
-reg_dir = os.environ.get('MAM_JOBS_DIR', '.mam/jobs')
+reg_dir = os.environ.get('MAM_JOBS_DIR') or (os.path.join(os.environ['WORKSPACE_ROOT'], '.mam', 'jobs') if os.environ.get('WORKSPACE_ROOT') else '.mam/jobs')
 p = os.path.join(reg_dir, f'{jid}.json')
 if os.path.exists(p):
     try: