refactor(confidence-engine): make episode preparation server-owned

components/scenario-form.jsx

@@ -6,7 +6,6 @@ import DiagnosticsView from "@/components/diagnostics-view";
 import ReasoningWorkspace, { LoadingOverlay, ContinueLaterBanner } from "@/components/reasoning-workspace";
 import { mockFetch, AVAILABLE_SCENARIOS } from "@/lib/mocks/confidence-engine/mock-client";
 import { deriveFindingsFromContributions, normalizeFindings } from "@/lib/graph/finding-helpers";
-import { prepareCompletedEpisode } from "@/lib/graph/episode-preparation.js";
 import { loadInvestigation, saveInvestigation, clearInvestigation } from "@/lib/storage/investigation-storage";
 
 /* Compile-time env resolution — NEXT_PUBLIC_ vars are injected by Next.js at build */
@@ -249,22 +248,10 @@ export async function executeEpisodeDone({
   targetNodeId,
   focusedContributions,
   findings,
-  prepareCompletedEpisode: prepFn = prepareCompletedEpisode,
   episodeDoneServer,
   synthesizeFn,
   setResult: setAppState,
 }) {
-  const prepared = prepFn({
-    situationGraph: resultSituationGraph,
-    targetNodeId,
-    contributions: focusedContributions ?? [],
-    findings,
-  });
-
-  if (!prepared?.turns?.length && !prepared?.eligibleCanonicalFindings?.length) {
-    return { success: false, stage: "preparation", reason: "no_episodic_content" };
-  }
-
   const serverResult = await episodeDoneServer({
     situationGraph: resultSituationGraph,
     targetNodeId,