fix(issue-18): default ack timeout T = 180 s

In the v4.5.0 review round grok read the brief and published `started`
70 s after the injection; with T = 60 the wrapper had already closed the
job as agent_blocked and refused its later PASS. T bounds delivery, not
work, so a generous default costs nothing when the agent answers fast.
Code, docs and the CLI snapshot updated together.

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

.agents/skills/multi-agent-mux-delegate-job/registry.md

@@ -201,7 +201,7 @@ $PY scripts/registry.py logs --list              # every job, live status
 | `heartbeat_sec` | N: the agent publishes `progress` at least every N s (the `--heartbeat N` timer does it) | 30 |
 | `heartbeat_misses` | K: missed heartbeats before the job is unresponsive | 4 |
 | `idle_timeout_sec` | K x N unless `--idle-timeout` was given | 120 |
-| `ack_timeout_sec` | T: `started` must arrive within T s of the injection | 60 |
+| `ack_timeout_sec` | T: `started` must arrive within T s of the injection | 180 |
 | `transport` | `herdr` (pane injection) or `remote` (signed retained dispatch over the broker) | `herdr` |
 
 `<registry>/<job>.heartbeat.pid` / `.heartbeat.log` belong to the running heartbeat timer; a terminal publish removes the pidfile.