fix(delegation): audit-log root follows the registry (Issue #57)

get_logs_dir(registry_dir) resolves the audit-log root as the
delegate_job_logs next to the registry in use when DELEGATE_JOB_LOGS_DIR
is not set; sibling_logs_dir() is the pure sibling rule. Every writer and
reader that knows its registry (registry, engine, publish_event, remote,
job_subscriber, reconcile.sh, the loop runner's fingerprint exclusion)
passes that root instead of falling back to the workspace default.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.agents/skills/lib_py/delegation/mqtt_common.py

@@ -183,20 +183,29 @@ EVENTS_FILENAME = "events.ndjson"
 STATUS_FILENAME = "status.json"
 
 
-def get_logs_dir() -> str:
+def sibling_logs_dir(registry_dir: str) -> str:
+    """The audit-log root that pairs with ``registry_dir``: its sibling
+    ``delegate_job_logs``. Pure; reads no environment. Issue #57."""
+    return os.path.join(os.path.dirname(os.path.abspath(registry_dir)), "delegate_job_logs")
+
+
+def get_logs_dir(registry_dir: Optional[str] = None) -> str:
     """Audit-log root, resolved at call time (B-9).
 
-    Overridable with ``DELEGATE_JOB_LOGS_DIR``; otherwise
-    ``$WORKSPACE_ROOT/.mam/delegate_job_logs`` (Issue #15, see
-    ``default_registry_dir``); otherwise ``<cwd>/.mam/delegate_job_logs``.
-    Resolved per call rather than at import so a chdir after import cannot
-    strand the audit trail in the old tree — the same reason
-    ``DEFAULT_REGISTRY_DIR`` stays a relative string.
+    ``DELEGATE_JOB_LOGS_DIR`` when set: it means the audit log was moved to a
+    place that cannot be derived from the registry. Otherwise the audit log
+    follows the registry (Issue #57): the ``delegate_job_logs`` next to
+    ``registry_dir``, or next to ``default_registry_dir()`` when the caller
+    does not know its registry. The default registry is
+    ``$WORKSPACE_ROOT/.mam/jobs`` (Issue #15), otherwise ``<cwd>/.mam/jobs``,
+    so the usual roots are unchanged. Resolved per call rather than at import
+    so a chdir after import cannot strand the audit trail in the old tree —
+    the same reason ``DEFAULT_REGISTRY_DIR`` stays a relative string.
     """
     env = os.environ.get("DELEGATE_JOB_LOGS_DIR")
     if env and env.strip():
         return env
-    return _workspace_mam_dir("delegate_job_logs") or os.path.join(os.getcwd(), ".mam", "delegate_job_logs")
+    return sibling_logs_dir(registry_dir or default_registry_dir())
 
 
 def __getattr__(name: str):          # PEP 562 (3.7+)
@@ -516,14 +525,15 @@ def _update_job_status_legacy(job_id: str, registry_dir: str = DEFAULT_REGISTRY_
         _atomic_write_record(job_id, registry_dir, record)
         if "status" in fields:
             new_status = record.get("status")
-            update_logged_status(job_id, new_status, updated_at=record["updated_at"])
+            logs_dir = get_logs_dir(registry_dir)
+            update_logged_status(job_id, new_status, logs_dir=logs_dir, updated_at=record["updated_at"])
             if old_status != new_status:
                 append_event(job_id, {
                     "event": "status_changed",
                     "from": old_status,
                     "to": new_status,
                     "timestamp": record["updated_at"],
-                })
+                }, logs_dir=logs_dir)
     return record