research: auto-transition processing → reviewing on last run

Hooks the topology_worker's post-terminal path into a new
notify_run_completed repo helper that atomically transitions the topic
processing → reviewing when the completed run has research_topic_id set
AND no siblings for that topic are still queued or running. Guarded on
status='processing' so a retry, a re-fire, or a topic already past
processing are all no-ops. Best-effort at the worker; DB hiccups are
logged and never fail the run.

The manual /submit-review endpoint stays as an escape hatch for topics
that end up parked in processing with nothing to complete (updated the
doc comment).

.sqlx/query-ebeb5ef13a40b1693425588096a4ec37dd01ecf6cd9c051aaf37399a69f617bf.json

@@ -0,0 +1,18 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "INSERT INTO topology_runs\n            (id, workspace_id, task, kind, status, graph, tier, research_topic_id)\n         VALUES ($1, $2, $3, 'run', 'queued', $4, 'team', $5)",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": [
+        "Uuid",
+        "Uuid",
+        "Text",
+        "Jsonb",
+        "Uuid"
+      ]
+    },
+    "nullable": []
+  },
+  "hash": "ebeb5ef13a40b1693425588096a4ec37dd01ecf6cd9c051aaf37399a69f617bf"
+}