Dashboard's ACTIVE DECKIES (active_deckies in get_stats_summary) counts
TopologyDecky rows where state='running'. No code path was flipping
that state away from the default 'pending', so the count read 0/N
even when every container was running fine — the dashboard was lying.
Two complementary fixes:
1. deploy_topology — after the post-deploy compose ps verification,
reconcile each TopologyDecky.state from the corresponding base
container's docker state. running → 'running'; anything else →
'failed'. Reuses the ps_rows already gathered for the
ACTIVE-vs-DEGRADED status decision; no extra docker hit.
2. apply_add_decky — _materialise_decky_spawn now returns True/False;
on True the row is updated to state='running' before
_assert_valid_after. Catches the case where a decky added via the
live mutator queue stays at 'pending' indefinitely (the deployer's
reconcile only runs on a fresh deploy_topology pass).
Existing topology deckies in active topologies will still read as
'pending' until the next deploy_topology runs, since this is
forward-only. An operator-side fix is to teardown + redeploy or run
the (forthcoming) reconcile-on-startup pass.