research pipeline v2: topology-aware start + persisted draft

Three connected changes that turn "Start research" from a status
flip into a real pipeline that produces a reviewable artifact:

- Migration 0036: adds research_topics.topology_kind (default
  'hub_spoke') and a new research_outcomes table
  (id, topic_id, version DESC, body_md, produced_by_run_id, created_at)
  so each run's final synthesis is versioned and persistent.

- Wizard now has a topology picker in the Outcome step —
  hub_spoke / pipeline / hierarchical / star_moe — with copy that
  steers users to the right shape (Pipeline for research → distill
  → analyze → implement rosters, hub_spoke for the coordinator-
  and-specialists default).

- start_topic reads the chosen topology_kind, parses it into a
  cm_topology::TopologyKind, and dispatches a per-shape coordinator
  prompt via build_coordinator_task. Pipeline explicitly tells
  stage 1 not to write the final artifact and propagates a
  "final stage MUST emit a complete markdown document with
  measurable acceptance criteria" instruction downstream. The
  graph builder is called with the topology the user actually
  picked instead of hard-coded HubSpoke.

- topology_worker::freeze_research_outcome fires after every
  successful complete(). It looks up research_topic_id on the run;
  if set and final_output is non-empty, it inserts a new
  research_outcomes row (version auto-derived server-side via
  coalesce(max(version), 0) + 1). Best-effort — a DB hiccup logs
  but doesn't fail the run.

- TopicDetail now includes topology_kind and latest_outcome.
  ResearchCanvas swaps in the outcome's body_md (rendered as
  pre-wrap markdown, versioned header, produced-at timestamp)
  whenever an outcome exists; the original prompt collapses into
  an "Original prompt" <details> below so it's still one click
  away. Pre-run topics still show the description as before.

Follow-ups still open: reject-with-revision loop feeding the
coordinator, publishing → published transition + real artifact
export (md / pdf), and an approvals inbox surface for reviewers.

crates/cm-db/src/repo/topology_runs.rs

@@ -147,6 +147,19 @@ pub async fn enqueue_run_for_team(
     Ok(())
 }
 
+/// The research topic this run belongs to, if any. Used by the topology
+/// worker's `freeze_research_outcome` post-hook to snapshot the run's
+/// final synthesis into `research_outcomes`.
+pub async fn research_topic_id(pool: &PgPool, id: Uuid) -> Result<Option<Uuid>, DbError> {
+    let row = sqlx::query!(
+        "SELECT research_topic_id FROM topology_runs WHERE id = $1",
+        id,
+    )
+    .fetch_optional(pool)
+    .await?;
+    Ok(row.and_then(|r| r.research_topic_id))
+}
+
 /// Enqueue a durable run bound to a research topic. `research_topic_id` is
 /// stored so `notify_run_completed` can flip the owning topic
 /// `processing → reviewing` when its last run terminates (see