FN-5733: enforce mission completion-gate assertions for live Goals mission

Realize the mission completion-gate contract by surfacing and enforcing structured assertion coverage for milestone completion.

- add milestone rollup signaling for prose-only acceptance criteria and wire it into mission-store completion gating
- update mission execution loop reliability paths so validator-trigger continuity is preserved across completion and startup recovery
- expose the new rollup flag in dashboard mission types/API and show an autopilot warning badge in MissionManager when prose exists without structured assertions
- extend core, engine, and dashboard tests plus mission docs, and add a patch changeset for @runfusion/fusion

Files changed:
 .changeset/fn-5733-mission-completion-gate.md      | 10 +++
 docs/missions-completion-contract.md               | 11 +++
 docs/missions.md                                   |  4 +
 packages/core/src/__tests__/mission-store.test.ts  | 81 ++++++++++++++++++++
 packages/core/src/mission-store.ts                 | 89 ++++++++++++++++++++++
 packages/core/src/mission-types.ts                 |  2 +
 packages/dashboard/app/api/legacy.ts               |  1 +
 .../dashboard/app/components/MissionManager.css    | 42 +++++++++-
 .../dashboard/app/components/MissionManager.tsx    | 22 +++++-
 .../components/__tests__/MissionManager.test.tsx   | 20 ++++-
 packages/dashboard/app/components/mission-types.ts |  1 +
 .../src/__tests__/mission-execution-loop.test.ts   | 23 ++++++
 .../mission-validation-trigger-gap.test.ts         | 41 ++++++++++
 packages/engine/src/mission-execution-loop.ts      | 21 ++++-
 14 files changed, 357 insertions(+), 11 deletions(-)

Fusion-Task-Id: FN-5733

Fusion-Task-Lineage: 259418c6-5404-4773-8fd2-db8d7e9cadd3

packages/core/src/__tests__/mission-store.test.ts

@@ -3032,6 +3032,49 @@ describe("MissionStore", () => {
       expect(events[events.length - 1].state).toBe("ready"); // linked but not passed
       expect(events[events.length - 1].rollup.unlinkedAssertions).toBe(0);
     });
+
+    it("flags rollup when milestone prose exists but no assertions are linked", () => {
+      const updatedMission = store.updateMission(mission.id, { status: "active" });
+      expect(updatedMission.status).toBe("active");
+      store.updateMilestone(milestone.id, { acceptanceCriteria: "Milestone prose" });
+
+      const warningEvents: Array<{ id: string; code: unknown }> = [];
+      store.on("mission:event", (event) => {
+        if (event.eventType === "warning") {
+          warningEvents.push({ id: event.id, code: event.metadata?.code });
+        }
+      });
+
+      const rollup = store.getMilestoneValidationRollup(milestone.id);
+      expect(rollup.hasProseButNoAssertions).toBe(true);
+      expect(store.milestoneHasProseButNoAssertions(milestone.id)).toBe(true);
+
+      const assertion = store.addContractAssertion(milestone.id, { title: "A1", assertion: "Temp" });
+      store.deleteContractAssertion(assertion.id);
+
+      expect(warningEvents.some((event) => event.code === "milestone_missing_structured_assertions")).toBe(true);
+    });
+
+    it("does not flag rollup when assertions exist", () => {
+      store.updateMilestone(milestone.id, { acceptanceCriteria: "Milestone prose" });
+      const assertion = store.addContractAssertion(milestone.id, { title: "A1", assertion: "Test" });
+      const slice = store.addSlice(milestone.id, { title: "Slice" });
+      const feature = store.addFeature(slice.id, { title: "Feature" });
+      store.linkFeatureToAssertion(feature.id, assertion.id);
+
+      const rollup = store.getMilestoneValidationRollup(milestone.id);
+      expect(rollup.hasProseButNoAssertions).toBe(false);
+      expect(store.milestoneHasProseButNoAssertions(milestone.id)).toBe(false);
+    });
+
+    it("does not flag rollup when neither milestone nor features have prose", () => {
+      const slice = store.addSlice(milestone.id, { title: "Slice" });
+      store.addFeature(slice.id, { title: "Feature" });
+
+      const rollup = store.getMilestoneValidationRollup(milestone.id);
+      expect(rollup.hasProseButNoAssertions).toBe(false);
+      expect(store.milestoneHasProseButNoAssertions(milestone.id)).toBe(false);
+    });
   });
 
   // ── buildEnrichedDescription with Assertions Tests ────────────────────
@@ -3149,6 +3192,44 @@ describe("MissionStore", () => {
     });
   });
 
+  describe("seedContractAssertionsForFeatures", () => {
+    it("seeds and links authored assertions idempotently", () => {
+      const mission = store.createMission({ title: "Seed mission" });
+      const milestone = store.addMilestone(mission.id, { title: "M1" });
+      const slice = store.addSlice(milestone.id, { title: "S1" });
+      const feature = store.addFeature(slice.id, { title: "F1", acceptanceCriteria: "AC" });
+
+      const beforeManaged = store.listAssertionsForFeature(feature.id).length;
+
+      const first = store.seedContractAssertionsForFeatures([
+        {
+          featureId: feature.id,
+          milestoneId: milestone.id,
+          title: "Authored assertion",
+          assertion: "Feature output is deterministic",
+        },
+      ]);
+
+      expect(first.created).toBe(1);
+      expect(first.linked).toBe(1);
+      expect(first.skippedExisting).toBe(0);
+
+      const second = store.seedContractAssertionsForFeatures([
+        {
+          featureId: feature.id,
+          milestoneId: milestone.id,
+          title: "Authored assertion",
+          assertion: "Feature output is deterministic",
+        },
+      ]);
+
+      expect(second.created).toBe(0);
+      expect(second.linked).toBe(0);
+      expect(second.skippedExisting).toBe(1);
+      expect(store.listAssertionsForFeature(feature.id).length).toBe(beforeManaged + 1);
+    });
+  });
+
   describe("backfillFeatureAssertions", () => {
     const makeLegacyFeature = (sliceId: string, input: { title: string; description?: string; acceptanceCriteria?: string }) => {
       const feature = store.addFeature(sliceId, input);