missions: phase-completion summary card (Claude Opus 4.8 synthesized)

New phase_summarizer background worker fires on any mission_phase
transition to a terminal state (completed/failed). Aggregates every
topology_runs.checkpoint.outputs[] + mission_tasks + mission_artifacts
bound to that phase and asks Claude Opus 4.8 to produce a structured
JSON card:

  { narrative, metrics, sources, tooling, next_actions }

Rendered inline on the mission page under each completed phase via
new PhaseSummaryCard component. Metrics grid is kind-specific:
research surfaces insights/sources/int_cards/artifacts, coding
surfaces cards_picked_up/commits/tests/issues, benchmark surfaces
regressions/improvements, security surfaces findings-by-severity.

New table: mission_phase_summaries (migration 0060), unique per
phase_id — regenerates on retry.
New endpoint: GET /api/missions/{id}/phases/{phase_id}/summary.

Model overridable via CLAWMATES_SUMMARIZER_MODEL. Reuses the
ANTHROPIC_API_KEY prod already carries for mission_refiner.

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

@@ -480,6 +480,51 @@ pub async fn retry_phase(
     Ok(Json(serde_json::json!({ "reset": true })))
 }
 
+/// GET /api/missions/{id}/phases/{phase_id}/summary — the completion
+/// card produced by `phase_summarizer` for a terminal-state phase.
+/// Returns 404 while the phase is still running / hasn't been
+/// summarized yet.
+pub async fn get_phase_summary(
+    State(state): State<AppState>,
+    Authed(user): Authed,
+    Path((id, phase_id)): Path<(Uuid, Uuid)>,
+) -> Result<Json<Value>, ApiError> {
+    // Scope check.
+    let _ = cm_db::repo::missions::get(&state.pool, id, user.workspace_id.as_uuid())
+        .await?
+        .ok_or(ApiError::NotFound)?;
+    use sqlx::Row;
+    let row = sqlx::query(
+        "SELECT kind, model, narrative, metrics, sources, artifacts,
+                tooling, next_actions, generated_at, error
+           FROM mission_phase_summaries
+          WHERE mission_id = $1 AND phase_id = $2",
+    )
+    .bind(id)
+    .bind(phase_id)
+    .fetch_optional(&state.pool)
+    .await?;
+    let Some(r) = row else {
+        return Err(ApiError::NotFound);
+    };
+    let generated_at: time::OffsetDateTime = r.get("generated_at");
+    let payload = serde_json::json!({
+        "kind": r.get::<String, _>("kind"),
+        "model": r.get::<String, _>("model"),
+        "narrative": r.get::<String, _>("narrative"),
+        "metrics": r.get::<Value, _>("metrics"),
+        "sources": r.get::<Value, _>("sources"),
+        "artifacts": r.get::<Value, _>("artifacts"),
+        "tooling": r.get::<Value, _>("tooling"),
+        "next_actions": r.get::<Value, _>("next_actions"),
+        "generated_at": generated_at
+            .format(&time::format_description::well_known::Rfc3339)
+            .unwrap_or_default(),
+        "error": r.get::<Option<String>, _>("error"),
+    });
+    Ok(Json(payload))
+}
+
 /// GET /api/missions/{id}/runs — topology_runs bound to this mission,
 /// newest first. Used by the Live tab to subscribe to per-run SSE.
 pub async fn list_runs(