fix(delegate): admission covers a rowless target and the installed parent of an incidental .mam (Issue #72, review round 2)

R1: a target with no registry row skipped the target gate. Its cwd is now
read from the live agent on the server delivery uses (resolve_herdr_session),
through the real herdr only when that server is running, so no server is
started; a herdr that cannot answer refuses before registration.

R2: any .mam counted as a workspace and stopped the walk, so B/sub/.mam hid
an installed B and the row's control_plane root was dropped. Workspaces are
now update.sh's installed trees (.mam_deploy/remove.sh or remove.sh): every
installed ancestor of the cwd, plus the recorded control_plane root.

lib_py.update target-workspaces prints them one per line; the wrapper holds
each on fds 20.. until the record is written.

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

.agents/skills/lib_py/update.py

@@ -16,11 +16,13 @@ this module what needs parsing. Standard library only, Python 3.9.
   python -m lib_py.update monitor --workspace W
       JSON {"pids": [...], "lock": "free"|"held"}: the monitor daemons
       daemon.find_running recognises, and whether .mam/monitor.lock is held.
-  python -m lib_py.update target-workspace --workspace W --agent-session S
-      The installed workspace a delegate target `herdr:<name>` belongs to
-      (decision 8), when it is not W: the nearest directory holding a .mam
-      at or above its row's pane.cwd, else the row's control_plane
-      workspace_root. Nothing for a rowless or non-herdr target.
+  python -m lib_py.update target-workspaces --workspace W --agent-session S --server V --herdr H
+      The workspaces other than W whose update admission a delegate submit
+      to `herdr:<name>` must take (decision 8), one per line: every installed
+      workspace at or above the target's cwd (its row's pane.cwd; with no row
+      the live agent's on server V) and its row's control_plane
+      workspace_root. Nothing for a non-herdr target. rc 1: herdr cannot
+      answer for a rowless target.
   python -m lib_py.update backup-registry --workspace W --dest D
       Copies the registry into D under the registry's own write lock
       (agent-sessions.db.lock, as atomic_yaml takes it): the DB through the
@@ -264,27 +266,46 @@ def precheck(workspace: str, state: dict, herdr: str, env: Mapping[str, str]) ->
 
 # --------------------------------------------------------------------------- delegate target
 
-def target_workspace(workspace: str, state: dict, agent_session: str) -> str:
+def _installed(d: str) -> bool:
+    """update.sh's own test of an installed workspace."""
+    return os.path.isfile(os.path.join(d, ".mam_deploy", "remove.sh")) or os.path.isfile(os.path.join(d, "remove.sh"))
+
+
+def target_workspaces(workspace: str, state: dict, agent_session: str, server: str,
+                      herdr: str, env: Mapping[str, str]) -> List[str]:
+    """Every installed workspace at or above the target's cwd - an update of
+    any of them counts that agent (decision 1) - and its row's
+    control_plane.workspace_root; the caller's own workspace left out. With
+    no row the cwd is the live agent's on <server> (the one delivery uses),
+    read with the real herdr. No herdr, a server that is not running, or no
+    such agent gives nothing (delivery then fails on its own); a herdr that
+    cannot answer raises HerdrError."""
     if not agent_session.startswith("herdr:"):
-        return ""
+        return []
     name = agent_session[len("herdr:"):]
     row = next((s for s in state.get("herdr_sessions") or []
                 if isinstance(s, dict) and s.get("name") == name), None)
-    if row is None:
-        return ""
-    found = ""
-    cwd = (row.get("pane") or {}).get("cwd") or ""
-    d = _real(cwd) if cwd else ""
-    while d and not found:
-        if os.path.isdir(os.path.join(d, ".mam")):
-            found = d
-        elif os.path.dirname(d) == d:
-            break
-        d = os.path.dirname(d)
-    if not found:
+    cwds, out = [], []
+    if row is not None:
+        cwds.append((row.get("pane") or {}).get("cwd") or "")
         root = (row.get("control_plane") or {}).get("workspace_root") or ""
-        found = _real(root) if root else ""
-    return "" if found == _real(workspace) else found
+        if root:
+            out.append(_real(root))
+    elif herdr and server in running_servers(herdr, env):
+        for a in server_agents(herdr, server, env):
+            if a.get("name") in (name, sanitize_herdr_agent_name(name)):
+                cwds += [a.get("cwd") or "", a.get("foreground_cwd") or ""]
+                break
+    for cwd in cwds:
+        d = _real(cwd) if cwd else ""
+        while d:
+            if _installed(d):
+                out.append(d)
+            if os.path.dirname(d) == d:
+                break
+            d = os.path.dirname(d)
+    me = _real(workspace)
+    return [d for i, d in enumerate(out) if d != me and d not in out[:i]]
 
 
 # --------------------------------------------------------------------------- monitor
@@ -344,9 +365,11 @@ def main(argv: Optional[List[str]] = None) -> int:
     s.add_argument("--herdr", required=True)
     s = sub.add_parser("monitor")
     s.add_argument("--workspace", required=True)
-    s = sub.add_parser("target-workspace")
+    s = sub.add_parser("target-workspaces")
     s.add_argument("--workspace", required=True)
     s.add_argument("--agent-session", required=True)
+    s.add_argument("--server", default="default")
+    s.add_argument("--herdr", default="")
     s = sub.add_parser("backup-registry")
     s.add_argument("--workspace", required=True)
     s.add_argument("--dest", required=True)
@@ -362,12 +385,18 @@ def main(argv: Optional[List[str]] = None) -> int:
         for line in lines:
             print(line)
         return 1 if lines else 0
-    if a.cmd == "target-workspace":
+    if a.cmd == "target-workspaces":
         try:
             state = _state()
         except ValueError:
             state = {}
-        print(target_workspace(ws, state, a.agent_session))
+        try:
+            roots = target_workspaces(ws, state, a.agent_session, a.server, a.herdr, os.environ)
+        except HerdrError as exc:
+            print("cannot find %s live: %s" % (a.agent_session, exc), file=sys.stderr)
+            return 1
+        for root in roots:
+            print(root)
         return 0
     if a.cmd == "monitor":
         print(json.dumps(monitor_state(ws)))