chore: establish learning module baseline

OpenMAIC/components/scene-renderers/pbl/v2/scenario-briefing-gate.ts

@@ -0,0 +1,23 @@
+/**
+ * PBL v2 — Scenario briefing visibility gate (SCENARIO ONLY).
+ *
+ * Single source of truth for "should the right column show the scenario
+ * briefing tab?". Kept as a tiny, dependency-free pure function (no React, no
+ * UI imports) so it is trivially unit-testable and cannot drift between the
+ * component and its tests.
+ *
+ * The briefing tab appears once the learner has ENTERED the scenario — i.e. the
+ * fixed first `prep` milestone is completed. `prep` only ever transitions to
+ * `completed` (never back), so this stays true for the rest of the run: through
+ * every roleplay stage, the wrapup, and after returning from the completion
+ * page (no active milestone). Non-scenario projects (no `project.scenario`) and
+ * scenario projects still in prep return false, so the workspace renders the
+ * bare submission panel exactly as before — zero footprint on those paths.
+ */
+
+import type { PBLProjectV2 } from '@/lib/pbl/v2/types';
+
+export function shouldShowScenarioBriefing(project: PBLProjectV2): boolean {
+  if (!project.scenario) return false;
+  return project.milestones.some((m) => m.scenarioStage === 'prep' && m.status === 'completed');
+}