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/lib_py/delegation/registry.py

@@ -52,10 +52,12 @@ def generate_job_id(bits: int = 32) -> str:
 # heartbeats (K x N seconds since the last event) as unresponsive; `started`
 # must arrive within T seconds of the prompt injection. K x N with these
 # defaults equals the historical 120 s idle timeout, so a caller that never
-# asked for the contract sees the same idle window as before.
+# asked for the contract sees the same idle window as before. T is generous:
+# a real agent reads the brief and reasons before it runs the start command
+# (grok took ~70 s in the v4.5.0 review round), and T only bounds delivery.
 DEFAULT_HEARTBEAT_SEC = 30
 DEFAULT_HEARTBEAT_MISSES = 4
-DEFAULT_ACK_TIMEOUT_SEC = 60
+DEFAULT_ACK_TIMEOUT_SEC = 180
 
 
 def liveness_window(heartbeat_sec: int, heartbeat_misses: int) -> int: