Show last run timestamp on ops automation status

Expose last_run_at / last_run on the status contract and display Last run
and Tasks columns on the /ops/ui status page for the selected window.

src/activity_core/automation_status.py

@@ -654,6 +654,11 @@ def classify_activity(definition: dict[str, Any], window: dict[str, Any], runs:
     else:
         status = "no_due"
 
+    last_run = latest_run_summary(runs)
+    temporal_last = None
+    if temporal and temporal.get("last_fired_at"):
+        temporal_last = temporal.get("last_fired_at")
+
     return {
         "id": definition["id"],
         "name": definition["name"],
@@ -666,6 +671,9 @@ def classify_activity(definition: dict[str, Any], window: dict[str, Any], runs:
         "expected_fires": expected,
         "expected_fire_count": len(expected),
         "observed_run_count": len(runs),
+        "last_run_at": last_run.get("fired_at") if last_run else None,
+        "last_run": last_run,
+        "temporal_last_fired_at": temporal_last,
         "runs": runs,
         "evidence": evidence,
         "temporal": temporal,
@@ -674,6 +682,26 @@ def classify_activity(definition: dict[str, Any], window: dict[str, Any], runs:
     }
 
 
+def latest_run_summary(runs: list[dict[str, Any]]) -> dict[str, Any] | None:
+    """Return the newest run by fired_at (then scheduled_for) within the provided list."""
+    best: dict[str, Any] | None = None
+    best_ts: datetime | None = None
+    for run in runs:
+        ts = coerce_datetime(run.get("fired_at")) or coerce_datetime(run.get("scheduled_for"))
+        if ts is None:
+            continue
+        if best_ts is None or ts > best_ts:
+            best_ts = ts
+            best = {
+                "run_id": run.get("run_id"),
+                "fired_at": run.get("fired_at") or iso(ts),
+                "scheduled_for": run.get("scheduled_for"),
+                "tasks_spawned": run.get("tasks_spawned"),
+                "version_used": run.get("version_used"),
+            }
+    return best
+
+
 def workflow_status_matches(workflow: dict[str, Any], names: set[str]) -> bool:
     value = str(workflow.get("status") or "").upper()
     return any(name in value for name in names)