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/multi-agent-mux-delegate-job

@@ -86,7 +86,7 @@ multi-agent-mux-delegate-job <command> [options]
           # Liveness contract: the agent heartbeats every --heartbeat N s
           # (default 30, automatic), the job is unresponsive after
           # --heartbeat-misses K x N s (default 4 x 30 = 120; --idle-timeout
-          # overrides), `started` must arrive within --ack-timeout T s (60).
+          # overrides), `started` must arrive within --ack-timeout T s (180).
   status  --job <id> [--registry-dir <dir>]
   list    [--registry-dir <dir>]
   verify  --job <id> --validate <script> [--registry-dir <dir>]
@@ -99,7 +99,7 @@ EOF
 AGENT="claude-code"; PROMPT=""; WORKDIR="$(pwd)"; AGENT_SESSION="herdr:claude"
 TIMEOUT=3600; IDLE_TIMEOUT=""; VALIDATE=""; DRY_RUN=0
 # Issue #18 liveness contract (N / K / T). An unset --idle-timeout derives K x N.
-HEARTBEAT_SEC="${MAM_HEARTBEAT_SEC:-30}"; HEARTBEAT_MISSES="${MAM_HEARTBEAT_MISSES:-4}"; ACK_TIMEOUT="${MAM_ACK_TIMEOUT_S:-60}"
+HEARTBEAT_SEC="${MAM_HEARTBEAT_SEC:-30}"; HEARTBEAT_MISSES="${MAM_HEARTBEAT_MISSES:-4}"; ACK_TIMEOUT="${MAM_ACK_TIMEOUT_S:-180}"
 JOB_ID=""; REGISTRY_DIR="$REGISTRY_DIR_DEFAULT"; DELEGATE_ROLE="Worker"
 TYPE="direct"; REVIEWER="hermes"; REVIEWER_SESSION="herdr:hermes"; MAX_ITERATIONS=5
 DEFAULT_COUNTERPART_ROLE="Reviewer"