research: wire start_topic to actually run the pipeline

The prior start_topic only flipped the status column — no work was
enqueued. Now clicking "Start research" actually launches the
assigned agents through the orchestrator.

- start_topic loads the topic + its research_topic_agents, picks a
  coordinator (first slot with role_slot containing "coordinator";
  else the first slot), and swaps it to index 0.
- Builds a hub_spoke topology graph via cm_topology::build with
  roles = [coordinator, spoke1, spoke2, …]. hub_spoke wires edges
  from the hub to every spoke and back, so the coordinator can
  address any specialist per turn.
- Assembles a coordinator prompt from the topic's title,
  description, outcome_kind, and a roster line for each teammate —
  so the coordinator knows who's on the team and what each does.
- Enqueues via a new topology_runs helper
  enqueue_run_for_research_topic that stores research_topic_id on
  the run row. `topology_worker::maybe_transition_research_topic`
  → `notify_run_completed` already picks up on that back-ref and
  flips the topic processing → reviewing when the last run
  terminates — that path was dead code until now.
- Per-agent activity streams into each claw's card for free:
  the orchestrator journals turn events into run_events; the
  existing /api/world/live SSE normalizer emits
  agent.reasoning.delta / agent.tool.call / agent.task.update
  keyed by agent id, which ClawCommandCenter is already
  subscribed to.

The `published` terminal state is still unreached (that's the
"publishing → published + artifact" step from the earlier
walkthrough — separate follow-up).

crates/cm-api/src/routes/research.rs

@@ -232,9 +232,15 @@ pub async fn detach_agent(
     Ok(StatusCode::NO_CONTENT)
 }
 
-/// `POST /api/research/:id/start` — flips status from `standby` to
-/// `processing`. Only valid transition on this endpoint; the reviewing +
-/// publishing hops come from the orchestrator and the publish approval gate.
+/// `POST /api/research/:id/start` — enqueue the research pipeline and flip
+/// status `standby → processing`. Builds a hub_spoke topology graph over the
+/// topic's assigned agents (first agent with role_slot="coordinator" becomes
+/// the hub; if none is designated the first assigned agent takes that role).
+/// The task string is a coordinator prompt derived from the topic's title,
+/// description, outcome_kind, and roster. The orchestrator drives the run;
+/// `topology_worker::maybe_transition_research_topic` flips the topic to
+/// `reviewing` when the last run terminates. Per-agent activity streams via
+/// `run_events` and lands on each claw's card through `/api/world/live`.
 pub async fn start_topic(
     State(state): State<AppState>,
     Authed(user): Authed,
@@ -246,6 +252,100 @@ pub async fn start_topic(
     if topic.status != "standby" {
         return Err(ApiError::Conflict);
     }
+    let slots = cm_db::repo::research_topics::agents(&state.pool, id).await?;
+    if slots.is_empty() {
+        return Err(ApiError::BadRequest);
+    }
+    // Hydrate names + job titles so the coordinator prompt names each teammate.
+    let mut roster = Vec::with_capacity(slots.len());
+    for s in &slots {
+        let agent =
+            cm_db::repo::agents::get(&state.pool, cm_domain::AgentId::from(s.agent_id)).await?;
+        roster.push((s.clone(), agent));
+    }
+    // Coordinator = first slot whose role_slot mentions "coordinator" (case-
+    // insensitive), else the first slot. The coordinator becomes the hub of
+    // the hub_spoke graph, so it can talk to every other agent per-turn.
+    let coord_ix = roster
+        .iter()
+        .position(|(s, _)| {
+            s.role_slot
+                .as_deref()
+                .map(|r| r.to_ascii_lowercase().contains("coordinator"))
+                .unwrap_or(false)
+        })
+        .unwrap_or(0);
+    if coord_ix != 0 {
+        roster.swap(0, coord_ix);
+    }
+    // Build a role list where element 0 is the coordinator (hub) and the rest
+    // are spokes. cm_topology's hub_spoke builder wires edges hub↔every spoke.
+    let roles: Vec<String> = roster
+        .iter()
+        .enumerate()
+        .map(|(i, (s, a))| {
+            if i == 0 {
+                "coordinator".to_string()
+            } else if let Some(r) = &s.role_slot {
+                r.clone()
+            } else if !a.job_title.is_empty() {
+                a.job_title.clone()
+            } else {
+                "specialist".to_string()
+            }
+        })
+        .collect();
+    let role_refs: Vec<&str> = roles.iter().map(|s| s.as_str()).collect();
+    let graph = cm_topology::build(cm_topology::TopologyKind::HubSpoke, &role_refs)
+        .map_err(|_| ApiError::BadRequest)?;
+    let graph_json_str = cm_topology::to_json(&graph).map_err(|_| ApiError::BadRequest)?;
+    let graph_value: serde_json::Value =
+        serde_json::from_str(&graph_json_str).map_err(|_| ApiError::BadRequest)?;
+
+    // Coordinator prompt: topic framing + roster + delegation instruction.
+    let roster_lines = roster
+        .iter()
+        .enumerate()
+        .map(|(i, (s, a))| {
+            let role = if i == 0 {
+                "coordinator (you)".to_string()
+            } else if let Some(r) = &s.role_slot {
+                r.clone()
+            } else if !a.job_title.is_empty() {
+                a.job_title.clone()
+            } else {
+                "specialist".to_string()
+            };
+            format!("- {} — {}", a.name, role)
+        })
+        .collect::<Vec<_>>()
+        .join("\n");
+    let task = format!(
+        "RESEARCH TOPIC: {title}\n\
+         OUTCOME KIND: {outcome} (spec / prod_plan / roadmap / paper)\n\n\
+         DESCRIPTION:\n{description}\n\n\
+         TEAM (hub_spoke — you are the hub, the rest are spokes you can address per-turn):\n{roster}\n\n\
+         YOUR JOB (coordinator):\n\
+         1. Break the topic into concrete sub-tasks and assign each to the best-fit spoke.\n\
+         2. Delegate turn-by-turn: each spoke's response feeds your next dispatch.\n\
+         3. Synthesize their outputs into a single {outcome} that satisfies the description.\n\
+         4. Cite each spoke's contribution where it lands in the final artifact.",
+        title = topic.title,
+        outcome = topic.outcome_kind,
+        description = topic.description,
+        roster = roster_lines,
+    );
+
+    let run_id = uuid::Uuid::now_v7();
+    cm_db::repo::topology_runs::enqueue_run_for_research_topic(
+        &state.pool,
+        run_id,
+        user.workspace_id,
+        &task,
+        &graph_value,
+        id,
+    )
+    .await?;
     cm_db::repo::research_topics::set_status(
         &state.pool,
         id,